Sen. Ron Johnson (R-WI) today predicted lawmakers would take President Obama to court if he deemed the debt ceiling is unconstitutional under the 14th Amendment. Liberals have floated the desperate and devious ploy in recent days to avoid spending cuts demanded by conservatives.

“If the president decides to do that — and that would be his decision and his alone — our only option at that point would probably be to take him to court,” Johnson said this morning on a call with reporters and bloggers. “If he does it, I’m just talking realistically here, I don’t know what Congress could do about it other than take him to court.”

Johnson, who has no plans to initiate a lawsuit himself, added that it would be a lengthy legal process and not likely to be resolved quickly. He said using the 14th Amendment argument would be a defining moment in Obama’s presidency and a factor in his re-election campaign. Obama has twice dodged direct questions about whether he would do this

“President Obama simply has not led,” Johnson said. “And let’s face it, that is the No. 1 job criteria of the president of the United States. I don’t know why he wants to be president if he’s not willing to lead.”

Congress placed a statutory limit on federal debt with passage of the Second Liberty Bond Act in 1917. Lawmakers have raised that limit 74 times since 1962. Only recently have liberals suggested the 1917 law conflicts with the 14th Amendment, which states that the “validity of the public debt of the United States … shall not be questioned.”

Johnson reiterated that he would vote for an increase in the debt ceiling as long as Congress instilled fiscal discipline, enacted a constitutional limitation and hard spending cap. At this point, however, he’s seen no willingness from liberals to budge. That prompted a passionate floor speech and call last week for the Senate to skip its recess.

They want to continue to spend the way they’ve always spent. They refuse to acknowledge that all these entitlement programs are unsustainable. They refuse to come to the table in good faith to strengthen these programs, to make them sustainable for future generations. They just want to put their head in the sand.

When asked about today’s reports that the White House might consider making changes to Social Security, Johnson criticized the Obama administration for a lack of transparency in the process.

“Reporters have more detail about what’s happening here in Washington on these debt-ceiling talks than rank-and-file members of Congress,” he said. “And to me, that’s outrageous, it’s disgusting, it’s not the way the process should work.”

UPDATE: Reuters reports the Treasury Department is secretly weighing its options to stave off default. Meanwhile, two of Johnson’s Republican colleagues have introduced a Senate resolution that warns Obama not to use the 14th Amendment ploy.