From the two assholes co-sponsoring the amendment, for starters:

Larry Craig, Daniel Vitter Co-Sponsors of "Marriage Protection Amendment"

I hope you don't have to be told who either of these senators are, but just in case: Larry Craig (R-ID), was caught playing footsie in a sex sting in an airport bathroom. Meanwhile David Vitter (R-LA), was one of the D.C. Madam's clients. The two have joined six others as co-sponsors of S. J. Res. 43, Sen. Roger Wicker (R-MS)'s "Marriage Protection Amendment." You can't make up stuff this good.

Other co-sponsors are: Sen. Wayne Allard (R-CO), Sen. Samuel Brownback (R-KS), Sen. James Inhofe (R-OK), Sen. Pat Roberts (R-KS), Sen. Richard Shelby (R-AL), and Sen. John Thune (R-SD).

The Amendment says in part:

Marriage in the United States shall consist only of the union of a man and a woman. Neither this Constitution, nor the constitution of any State, shall be construed to require that marriage or the legal incidents thereof be conferred upon any union other than the union of a man and a woman.

Besides the obvious irony just based on the fact of the two of them cheating on their wives, it's even worse for Craig obviously, as he would be shutting the door on any potential gay marriage in his future. Heh. (source)

DC has either absolutely no appreciation of humor, or such a tremendous sense of it, they're willing to let these two back into the Senate.