From former Alaska Gov. Sarah Palin to Arizona Sen. John McCain to junior members of the House of Representatives , conservative Republicans have accused President Barack Obama of failing to do all he can to help clean up the Gulf of Mexico oil spill because he hasn't waived a U.S. maritime law called the Jones Act.

That statute, established in 1920, requires that all goods transported between U.S. ports be carried on U.S.-flagged, U.S.-built and U.S.-owned ships crewed by U.S. citizens or permanent residents. Critics say that's needlessly excluded foreign-flagged vessels that could have helped.

"It's a little shocking to me that a president that has such a multinational orientation as this president didn't immediately see the benefits of waiving the Jones Act and allowing all of these resources to come in," former House Majority Leader Richard Armey , R- Texas , said in remarks to Newsmax.com, a conservative website.

Armey and the other Republican critics are wrong. Maritime law experts, government officials and independent researchers say that the claim is false. The Jones Act isn't an impediment at all, they say, and it hasn't blocked anything.