Tea Party activist Bob Guzzardi informs me that Obama/Geithner cannot default because of the 14th Amendment doesn’t permit them to.
“The Ds are reading 14th Amendment backwards,” Bob points out. He says that Sen. Mike Lee, R-Utah, who clerked for Supreme Court Justice Sam Alito explains at 2:18 in the video at this link the 14th Amendment doesn’t allow default and, in clearest reading, requires that debts be honored.