Back in the 1980s President Reagan signed an income tax treaty with China in Beijing so as to prove his trip a success. The treaty was a mess: Treasury negotiators had orders to produce a treaty for him to sign, and they did — with huge giveaways to corporations that artificially routed transactions through China. See http://ia600409.us.archive.org/16/items/preparedstatemen1185ogle/preparedstatemen1185ogle.pdf.
But signing does not a treaty make. The Senate must approve it. The most liberal Senator, Howard Metzenbaum of Ohio, put a hold on the treaty for allowing giveaways to multinational corporations; the most conservative Senator, Jesse Helms of North Carolina, put a hold on it for being too lenient with Red China. Those holds stopped the treaty in its tracks. Treasury went back, renegotiated, and eliminated the loopholes. Eventually, the repaired treaty came back to the Senate and sailed through.
Now the most liberal and the most conservative members of the U.S. House of Representatives join forces against the status quo.
Barney Frank and Ron Paul propose legalizing marijuana. http://ca.news.yahoo.com/lawmakers-introduce-bill-legalize-marijuana-225335489.html. Time will tell how this turns out.