On Capitol Hill this year, one of President Obama’s most troublesome critics has been Senator Obama.

President Obama, for instance, wants Congress to raise the national debt limit. But his opponents have brought up a statement that then-Sen. Barack Obama made in 2006: The first-term Democrat representing Illinois said that merely debating a debt-limit increase was “a sign of leadership failure.”

President Obama now insists that he had the right to dispatch U.S. forces to the conflict in Libya without authorization from Congress. Critics have noted that Sen. Obama seemed to feel differently about the proper use of military force in 2007.

Rep. Dennis J. Kucinich (D-Ohio) even carries a quote from Sen. Obama in his pocket, to show people who don’t believe it.

“The president does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation,” Obama said four years ago.

The past is always an occupational hazard for presidents, who find themselves disowning statements they made when they were candidates or legislators embroiled in partisan fights.

But Obama seems to have gotten himself into unusually hot water this year. In three different battles, his own words have become weapons for both Democrats and Republicans.

Asked about the apparent contradictions last week, a White House spokesman said that “the president has already explained his position on each of these issues, and we will let those responses speak for themselves.”

On the debt ceiling, Obama has said his past position was a mistake. Moreover, he has called on Republicans not to make the same mistake.

Two views of war powers

But on Libya, the president’s past words appear to have forced him into legal contortions. As a senator, Obama spoke with respect about the 1973 War Powers Resolution, a law that requires presidents to get congressional authorization after sending U.S. forces into hostilities abroad.

Now, Obama has sent forces to the simmering conflict in Libya and has missed that same law’s deadline to get approval from lawmakers.

But as commander in chief, Obama’s argument for this is not that the law is unconstitutional, as other presidents have contended. It is, instead, that the law simply doesn’t apply.

Because U.S. forces primarily play a supporting role in the NATO-led Libya operation, and because Libyan forces are too battered to retaliate effectively, Obama declared that this conflict does not amount to “hostilities.”

But House Republicans are incredulous, as are some House Democrats. Friday, in a rebuke of Obama, a restive House voted not to authorize the Libya campaign. The chamber then, however, rejected a bill that would have eliminated funding for offensive operations in Libya, such as airstrikes and drone attacks.

“Senator Barack Obama would be among the Obama administration’s fiercest critics,” said Michael Steel, a spokesman for House Speaker John A. Boehner (R-Ohio). “In 2007, he urged Congress to stand up to the White House, but now . . . he’s hiding behind the claim that there’s nothing hostile about bombs, missile strikes and Predator drones.”

The next step in this fight will come in the Senate, where a committee this week will take up another resolution to authorize the conflict. In the House, Kucinich and Rep. Justin Amash (R-Mich.) have said they will try to strip all funding for the operation when the session resumes in July.

“You start to see that the president’s straining here. I have a lot of compassion for the situation he’s in, but . . . I can’t let that stop me from challenging the path that he’s pursuing,” said Kucinich, who has helped stir up opposition to Obama over Libya. He said he carries around Obama’s 2007 quote so he can show it to the president’s supporters on the conflict.

“It kind of stops the conversation,” Kucinich said. “You know, people don’t know what to say.”

Already, Sen. Obama’s opinion that presidents shouldn’t enter conflicts without congressional approval has been written into a Senate measure. That was the idea of Sen. Rand Paul (R-Ky.), who wanted to pass a “sense of the Senate” resolution that Obama had been right in 2007.

It failed, earning just 10 votes, all from Republicans.

In March, NBC’s Brian Williams asked Obama to explain the apparent contradiction between his previous and current Libya views. The president said that he had to launch the Libya campaign quickly and that he consulted with congressional leaders before starting the operation.

“The key point here is that this is not a situation analogous to Iraq, in which we are devoting ground troops and a long, protracted battle that puts American lives at risk,” he said.

More recently, Obama’s spokesman tried to turn the same tactic against Boehner, who has challenged the president over the War Powers Resolution and Libya. Press secretary Jay Carney told reporters this month that Boehner said in 1999 that he thought the War Powers Resolution was “constitutionally suspect.”

“So do you think Speaker Boehner is playing politics now?” a reporter asked.

“I simply think it’s important to know what his views were then,” Carney said.

Boehner’s response has been that back then, he was just a member of Congress. Now, he’s the speaker and must defend the law of the land.

A familiar dilemma

In the past, longtime lawmakers’ previous statements and votes have come back to dog them as presidential candidates. Take Sen. John F. Kerry (D-Mass.), who famously said that he voted for a bill to fund the Iraq and Afghanistan wars before he voted against it. They have also tripped up presidents in office: George H.W. Bush pledged “Read my lips: no new taxes” during the 1988 campaign then was blasted as president after he agreed to a tax increase.

This year, Obama’s troubles with himself have not been limited to Libya.

GOP senators, for instance, have sought to block many of Obama’s judicial nominees with the threat of filibusters. As an example, they have cited Sen. Obama, who voted in 2006 for a filibuster against one of President George W. Bush’s nominees, current Supreme Court Justice Samuel A. Alito Jr. That filibuster attempt failed.

On the issue of the debt ceiling, Republicans have repeatedly quoted a speech that Obama gave in 2006 on the Senate floor. At the time, President Bush was the one asking for an increase in the limit. Obama was among those lawmakers seeking to mine the political benefits from opposing a bill that everyone expected to pass.

“Increasing America’s debt weakens us domestically and internationally. Leadership means that the buck stops here,” Obama said then. “Instead, Washington is shifting the burden of bad choices today onto the backs of our children and grandchildren. . . . I therefore intend to oppose the effort to increase America’s debt limit.”

Obama voted against the bill, but the measure passed the Senate anyway, with 52 votes that all came from Republicans.

In April, Obama told ABC’s George Stephanopoulos that his vote against raising the debt ceiling had been a mistake. He appealed to the current Congress to vote yes, saying that Sen. Obama was a bad example to follow.

“I think that it’s important to understand the vantage point of a senator versus the vantage point of a . . . president. When you’re a senator, traditionally what’s happened is [raising the debt ceiling] is always a lousy vote. Nobody likes to be tagged as having increased the debt limit for the United States by a trillion dollars,” Obama said. “As president, you start realizing: ‘You know what? We can’t play around with this stuff.’ ”