Rmoney wants it signed as soon as possible:
Trans-Pacific negotiations have been taking place throughout the Obama presidency. The deal is strongly supported by the U.S. Chamber of Commerce, the top lobbying group for American corporations. Obama's Republican opponent in the 2012 presidential elections, Mitt Romney, has urged the U.S. to finalize the deal as soon as possible.
http://www.huffingtonpost.com/2012/06/13/obama-trade-document-leak_n_1592593.html
In contrast, the Administration wants to have it signed later.