Let's have a look what supporters of the English Imperial system have to say and why it's all nonsense:

We have a perfectly good measuring system, so why does the USA have to change to using the metric system?

No, we don't have a perfectly good measuring system! We have a clumsy, entangled, confusing measuring system! And it not only confuses the rest of the world - no, it perplexes Americans themselves!

If you go to buy carpeting, and you need 100 square feet, the carpet costs $10 per square yard, could you, even given these simple numbers, ever figure out how much you'll pay? Which is more, 2 quarts, 5 pints or 36 fl oz? How many pints are in a gallon? How many pounds are 200 ounces? Which drill is the larger - the 13/64, the 1/4 or the 5/32? Two cities on a map are 10 inches apart - what is their real world distance?

Do you have to default on these questions? Then you have a problem - a problem called English Imperial system.

But the English system represents our culture and traditions, it's our heritage - we can't give it up!

First of all - the English system is not American - it's English! So on which cultural grounds are you claiming something English as American heritage while you reject something French as alien?

In fact, a large part of American culture is actually European culture, not only is the measuring system, but also language, religion, architecture etc. Sure did Americans tweak this heritage, but the essence stays European. On the other hand, many innovations are originally American, like much modern technology, music culture, and life-style - and these are truly to be proud of. The English system though is definitely not among them - it's not American, and it's not to be proud of either.

The world is continuously changing, and humans are ceaselessly improving their living conditions. That includes getting rid of old, stupid procedures and habits, and acquiring new, more intelligent procedures and habits.

Don't you think it caused a hell of a protest each time the English system 'evolved'? When all the slightly different feet were unified in one standard foot, all the pounds in one pound, all the various gallons in one gallon. How many beloved medieval units had to go and how many Englishmen were plunged into an identity crisis to make room for what is now called English system!

Culture and traditions of the U.S. as a young country were always evolving and changing - they were defined and are maintained and represented by the people who live here. Now it is time to define a new part of culture. Would you really stick with a stupid habit just because you always did it such a way? Would you continue to use a horse cart instead of a van just to honor your grandfather who always used one? Would you dig a well in your garden instead of having running water just because that's where all your ancestors got their water from? Can you be truly proud of something that is silly?

And, most importantly, would you not take some good advice just because it was not your idea? Would you be a fool for the sake of being different? Is that American pride or American folly?

Be proud of the constitution, the Space Shuttle, the Internet, the Pentium processor, but - please - don't be proud of the English system.

The rest of the world imposes the metric system on us!

No, other countries are just going to refuse import of goods that are not to metric specification. This is every country's free choice, and in fact the U.S. 'impose' all kind of specifications on its imports, too. The U.S. even impose sanctions on other countries which export to other countries, like Cuba or Iraq! Might you find this rightful or not, it's compulsory and by no means democratic.

The rest of the world made the free decision to adopt the metric system while the U.S. decided to stay with the English Imperial system. Had the U.S. started to convert early, would there be neither significant costs nor difficulties. Now though, that the world is moving on but we chose stagnation, we are facing the consequences.

In the 1980s Japanese cars became increasingly popular, simply because they were the better product, and sale of U.S. cars declined because people just won't buy crap only because it's American. Fortunately the U.S. automotive industry understood, and the result is even better cars. Applying dogmatic traditions and blind vanity to a progressive economy just doesn't work.

Why should we switch to metric just because all other countries did?

Right, we should not switch to metric just because all other countries did - we should switch because the metric system is the better system! Because science, education and business have already and will profit more from the better system in the long run. Ask scientists, engineers, teachers! Don't ask those who consider our system of measurement an instrument of pride, while it's really only an instrument of measurement.

This discussion is often confused with a battle English against metric, with a struggle of two fanatics for world domination. Power was never the aim of the metric system's fathers and advocates. The goal was from the very beginning to establish a simple, easily used system of weights and measures to simplify international trade and scientific research. Is it a minority complex or a rebellion without a cause that makes some Americans turn this technicality into a crusade?

After all not all other countries switched to metric!

Well, except for the rest of the world two third world countries haven't officially committed to the metric system: Liberia and Burma. But they already use metric units all over the place and are well on way leaving the sinking Imperial ship. So who's going to get wet?

America became the great country it is using the English system!

How about: America became the great country it is despite using the English system! And it could be an even greater country without it!

American units naturally evolved, while metric units were arbitrarily defined.

Oh come on, at some point in time, every unit on this planet was arbitrarily defined by someone. Regardless if referencing human feet or the earth's circumference.

In metricated countries, non-SI metric units live on, because they are more useful, like the centimeter, or the French quintal.

First of all, the centimeter is a valid SI unit, and actually many other metric units, though not recommended by SI, are allowed nevertheless, like bar, hectare and ton. Yes, the quintal, though metric, is not allowed under SI. However, all of these units can be scaled to SI units by powers of 10, i.e. just by shifting the decimal point (1 bar = 100,000 pascal, 1 hectare = 10,000 m², 1 ton = 1,000 kg, 1 quintal = 100kg). Also, all non-metric units have been redefined to exact metric values, e.g. 1 pound = 500g, 1 pint = 500ml. And, even though not strictly part of SI, these units are metric and do not constitute a contradiction to its philosophy.

Some non-metric units though, like the horsepower, are still around for completely irrational reasons. E.g. in metric the power of a car is specified in kilowatts, like 85kW. However, the same power in hp (114hp) sounds more. Therefore, to impress naïve customers, European car dealers tend to supply translations of their cars' power to hp!

After all, the SI system is a standard for science and trade, not a tool to oppress people as you like to view it. Everyone can in their private life measure any way they like.

And you are applying in an unfair way different scales to both systems: You picture the English system as the system of the people, the metric system as the system of the bureaucrats. This is simply not true. To reduce the medieval hodgepodge of gazillions of similar, but still not quite equal units into the at least somewhat usable nowadays English system did sure require major bureaucratic interventions. And common people all over the world have used the metric system for generations and like it. Yes, like it.

Look at definition and use of each system separately. It's not that the English system is just used, while the metric system is only defined. Both systems are both defined and used, and the metric system is truly superior in both definition and use.

Many metric countries even still use English Imperial units.

Still is the right word. There are a few traditions which are very deeply established. While thousands of other things are measured in metric units, for example tires and pressure plumbing are manufactured to imperial specifications throughout Europe. In fact, you can buy plumbing supplies in Europe and they will fit here. But — the so-called inch pipe names are nominal numbers that do not reflect an actual size. There is nothing 1/2 inch about a half-inch pipe. In fact there are different standards for pipe sizes depending on whether it is water pipe, gas pipe, or electrical conduit. Half-inch water pipe is really 16 mm inside diameter and 18 mm outside diameter. Neither of these comes close to 1/2 inch.

And after all even these are dying standards based on outdated traditions. In the automotive industry (even U.S. companies), imperial parts are step by step replaced by metric parts. Will the plumbing or tire industries experience paradigm shifts in the future (and they will for sure, e.g. polymer plumbing), the new technology will be for sure to metric specifications. And — since imperial units are officially defined in terms of metric units, everything to imperial specification is automatically and inevitably to metric specification anyway.

After all the U.S. economy, per capita, is bigger than the EU's and the U.S. has a greater role in world trade and politics.

1.  Actually Luxembourg has the world's highest GDP (Gross Domestic Product) per capita, so let's Luxembourg (an EU member!) decide.

2.  To measure the total economical power, you have to consider the total GDP. And currently, we can very well talk about equal powers here. The U.S. (9192.0 B$) outweighs the EU (8487.8 B$) only marginally, and already only OECD Europe (9349.7 B$) is economically stronger than the U.S.. Not to mention the rest of the metric world like Japan (4320.2 B$). (data for 1999 from oecd.org)

3.  Sure does the U.S. as a single country have the strongest economy and the strongest military in the world. This enables the U.S. to take an important role in economics and politics. However, since long ago world economy and world politics is not about single countries any more. And this role is not a position assigned by other nations, but self-assumed. There is nothing bad about this, except that any right you deduce from this fact is again self-assumed. With other words, a statement based on an opinion stays an opinion. Let's try to impose the English system on the rest of the world and see what happens!

The French people did not readily take to the metric system.

People in general do not readily like anything new, regardless of its usefulness. This common detest of change does not in any way disprove its usefulness.

In fact, wouldn't you agree that all the many changes that America underwent on its way from a 17th century British colony to nowadays progressive nation were in fact seldomly welcomed?

Every innovation, every bit of progress had to survive the malicious resistance of outdated people pretending to preserve traditions but only hampering progress and prosperity.

The introduction of the metric system does not undergo a democratic process. Who ever asked the American people if they want to have part of their culture erased by metricators?

The U.S. have a so-called representative democracy. Decisions are not made by the people, but by representatives elected by the people. These representatives then make laws, decide if to engage in war with other countries, or if to update weights and measures. If you wanted a public ballot on the metric system, you would have to question how democracy works in the U.S. in general, and that is a whole different topic.

The metric system in the U.S. has spread through the lobbying and implementation efforts of bureaucrats, technocrats and other individuals and bodies not representative of the majority of the population.

Well, bureaucrats and "technocrats" are appointed through elected federal, state or city governments, and are therefore in fact representing the majority of the population. We could engage in discussion how democratic U.S. democracy really is, but that is not a problem of the metric system.

Other individuals and bodies put up their web sites, making use of their right of free speech, and never claimed themselves representatives of the majority of the population!

The European Commission is forcing metric units on the UK by prohibiting traditional units. No Brit ever asked them to do so.

First of all, the UK decided to adopt the metric system out of their own free will, and well before they joined the EU. The trouble with the EU government came about only because the conversion process went ahead rather slowly. And then, after all, a union always means compromise. You cannot expect to only benefit from a union and never give in. If the British never wanted to compromise on any of their traditional values, they would have better never joined the EU. And adopting a new system of measurement consequently means abolishment of the old system, otherwise we would not gain anything except even more confusion, right?

How about the U.S. federal government forcing all kind of directives on the individual states? Why is no one complaining that the federal Supreme Court can outrule (and does) any state court?