The list of issues on which Barack Obama has flipped now that the primaries are over is long and growing rapidly.

• He says he believes in a Second Amendment right to bear arms.

• He now opposes late-term abortion.

• He suddenly is a devotee of using faith-based institutions to deliver public services.

• He now says that he won’t raise Social Security taxes on anyone making less than $250,000 a year. In the primary, he said he’d eliminate the threshold entirely, including on people making as little as $100,000.

• He recently opposed the Fairness Doctrine for talk radio.

• Now he says he’s going to consult with the military before pulling out of Iraq.

But so extensive a list of flip-flops, all in the past few weeks, begs the basic question: Was he lying before when he was a liberal, or is he prevaricating now?

Even if Obama means what he is saying as he moves to the center trying to win the general election, the fact is that he will be forced to move very far to the left should he become president, forced by the liberals in his own party.

If Obama wins, it’s more than likely that he will take office with a Congress filled with Democrats and liberals. Most probably, the Senate will have at least 55 Democrats (including pickups in Colorado, New Mexico, Virginia, New Hampshire and Alaska). And there might be as many as 62 (possible Democratic pickups include Maine, Minnesota, Oregon, Kentucky, Texas, Kansas and North Carolina). The House will, of course, be solidly in Democratic control.

Faced with the same situation in 1993, as he took office as president, Bill Clinton found no alternative but to move dramatically to the left, shelving for the moment his promises of a middle-class tax cut and welfare reform. He had no choice. The Democratic majorities in both Houses served him with notice: Either you stay within the caucus and not cross the aisle in search of support for centrist policies, or we will do unto you what we did to Jimmy Carter when Tip O’Neill turned on him and made his life miserable. Clinton was forced to emphasize healthcare reform over welfare changes and to go with a liberal economic stimulus package capped by big tax increases. The liberal stain sank so deeply into the fabric of his presidency that it caused him to lose Congress in 1994, and almost to lose the 1996 election.

It will be the same with Obama. On all of his basic issues, the Democrats in Congress will hold his feet to the fire and make him govern to the left. On his signature issue of Iraq, he may find himself with a war already won, a democracy already stable and a problem already solved. Nevertheless, he will be forced to rip the scab from the wound and set it bleeding again by bringing our troops home prematurely. His healthcare proposals will be forced far to the left until they amount to a government takeover of the healthcare system. Obama will not be able to govern from the center. His party won’t let him do it.

Ultimately, Bill Clinton’s congressional supporters became his jailers and he morphed from their leader into their hostage. Dependent on every last Democrat to pass legislation in the House and to prevail over a filibuster in the Senate, he found himself pushed further and further to the left until, he told me, “I don’t even recognize myself.” He had to lade his economic and anti-crime package with pork to satisfy urban congressmen and to win their support of a bill that included a federal death penalty.

Obama will not be able to help himself. The Democratic majority in Congress won’t settle for triangulation. They will make the Obama of November into a liar and the Obama of the primaries into an honest man.