The conversion of the United States
There seems to be the general impression in the United States that the metric system was something that they tried years ago and it didn't stick. It is true that there have been some initiatives with only limited success (such as for highway construction in the 1990's), but that hardly means the end of metric conversion in the U.S. It will always be an issue until we change. Metrication is inevitable as the world becomes more global and as the metric system becomes more and more entrenched in engineering, business, and everyday life in countries everywhere.
What has been happening
There was a push to convert the United States back in the 1970's. Similar programs were quite successful in many countries (such as Australia), but in the United States the effort was largely derailed by a lack of commitment. Since that time, metrication has been occurring at a slow pace. Many of our industries and corporations have been converting and often use metric. These include the automotive industry, electronics companies, and companies such as Kodak. Most recently, consumer products have started appearing in metric sizes (such as some shampoo, mouthwash, bottled drinks, etc.). Over the past few decades, while we have been making slow progress in conversion, countries around the world have been developing their economies and solidifying their use of the metric system.
Where we are now
The attitude of many in America has been that others should just deal with our measurement system. However, 95% of the world now lives in countries that are entirely or mostly metric.1 Worldwide use of the metric system has solidified even during America's reign as superpower. We simply are not able to impose our system on the rest of the world. Many other countries are recognizing this and they are taking steps to enforce metric usage in trade because metric units are the accepted international standards. Many of our trading partners require or soon will require all imports of commodities to be labeled in metric units only.
For example, it is against the law for a company to import a soft-drink bottle into Korea if it is labeled "20 FL OZ (591 mL)".2 It would be filled to 600 mL and be labeled in milliliters, no ounces allowed. Similar laws will apply in the European Union within a few years. Thus, a global soft-drink manufacturer needs two different product lines (with different product sizes) to maintain the U.S. measures in the United States. Some trade groups have complained that these laws are protectionist measures, but they simply require that the accepted standards be followed. U.S. companies are not penalized if they just comply. For this reason, many large U.S. companies have already converted their products to metric sizes, and many more will do so in the near future.
What happens next
In order to help our companies produce goods for a world market, some (including Procter & Gamble and Georgia-Pacific) are suggesting that we change U.S. law to allow metric-only labels on consumer goods. This means that customers will be seeing more and more metric when they go to the grocery store.
In 2005, proposed legislation to allow metric-only labeling was going to be submitted to Congress, but it was not, primarily because of opposition from the Food Marketing Institute. It is not clear what will happen next, but the European Union was given assurance in 1999 that the legislation would be passed by 2010 so that we can stop inflicting our units of measure on them in international trade. Expect some annoyed Europeans (and possible fines) if we continue to drag our feet.
If you would like to help move us down the road to metric usage, consider joining The U.S. Metric Association. Your membership fee will go to support metric initiatives, and you will get a newsletter to keep you informed with news and information.