House Democrats are urging President Obama to invoke the 14th Amendment should Congress fail to meet the president's Aug. 2 deadline for a long-term debt-ceiling increase. "We have to have a fail-safe mechanism," said Democratic-caucus chairman John Larson of Connecticut. The amendment states that the public debt cannot be questioned, words Democrats believe would make the debt ceiling unconstitutional. Although Obama has expressed some doubt about whether he has the legal right to singlehandedly raise the debt ceiling, Larson says, "We just want to let him know that his caucus is prepared to stand behind him." Former president Bill Clinton has said he wouldn't give the invocation a second thought, and then leave it to the courts to figure out.