Mandating a switchover to metric in the US could be a nice little country-specific policy.
Capitalists would be pleased that products could be made to a single worldwide standard, international trade would slightly increase, and an Uncompetitive Economy would be mildly reduced. Arguably small business owners and the self-employed would be a bit unhappy, since businesses that sell mainly domestically would have less to gain, but still be required to alter their manufacturing processes.
Patriots would be displeased for obvious reasons, and foreign relations would increase slightly for the visible effort towards internationalization.
There would be a small cost to pay for changing road signs, education campaigns, rewriting regulations, etc.