Liberals’ reaction to President Obama’s acceptance speech at the Democratic National Convention was instructive. Sure there were the diehards, who insisted the message was still invigorating and the messenger still inspirational. But more than at any time in his presidency, the left-leaning pundits let him have it.

Perhaps the shock of such a dismal delivery prompted a spasm of honesty. But it may also be that Obama’s utility to the left is waning.

Obama is the only true man of the left to make it to the White House. Unlike his predecessors (both Democrat and Republican) he seeks to downsize America's footprint in the world, not expand it. He looks upon the United States as responsible for many of the world’s ills, and therefore at its best when America is doing the least. He sees the economy as a fixed sum game in which, as he famously put it, you have to share the wealth. (Take from one group and give it to another.) We have never had a president as aggressively anti-business as this one.

That makes the stakes very high for the left-wing base of the Democratic Party. What if Obama can’t succeed from either a policy or a political standpoint? In other words, what if the closest we’ve had to undistilled liberalism in the White House is a failure?

This is the potential dilemma for the left, which I suspect will rear its head more frequently as we get closer to Election Day.

If liberal elites see Obama’s poll numbers going south, get ready for an all-hands-on-deck effort to separate Obama from liberalism; the former may lose but the the left cannot allow the latter to be repudiated. Now they are in full self-delusion during the post-convention bump, but when reality (and the jobs numbers) hit home watch for the excuse storylines to creep in. The campaign blew it by going negative too early. Obama’s team mismanaged the convention. He should have attacked even more. The details will differ, but the conclusion will be the same -- incompetent campaign management will be responsible for any loss.

The other variation is that Obama is personally unsuited to the presidency so the left’s agenda never was properly implemented. This is compelling in part because Obama has been remarkably inept. His remote personality, which was a boost in the 2008 election, became a liability in practice.

With the publication of Bob Woodward’s book detailing the debt ceiling debate both conservatives and liberals will have a treasure trove of evidence that Obama, unlike Ronald Reagan, LBJ and Bill Clinton, could never get 3/4 of a loaf, never engage and charm the opposition and never grasp that insulting and humiliating the opposition will spur them to go for the jugular. (In the book Obama tries to characterize the speech in which he lectured Rep. Paul Ryan a “mistake.” Woodward quotes the president: “I might have modified some of it so that we would leave more negotiations open, because I do think that they felt like we were trying to embarrass him . . . We made a mistake.”) Rather than find fault with the agenda (raise taxes on the rich in a recession, defend the status quo on entitlements) it’s comforting to think if not for Obama’s atrocious interpersonal skills they could have gotten a liberal nirvana.

You say it will never happen, that liberals will not cast off their political messiah? Think again. They already have shown how eager they are to defend their ideology at the expense of the president. Paul Krugman has been excoriating the president for years for too little borrowing and spending. He blew it !After all, what other explanation can there be for the abject failure of Keynesian policy?

Likewise, the left would never be comfortable acknowledging Obama’s Democratic National Convention speech was rotten not because his agenda — their agenda — is faulty. To eye-rolling conservatives, it smacked of warmed over statism from the last century. (Supply-sider Larry Kudlow sums it up: “it’s more money for the teachers unions, or more Solyndra-like green energy, or more for infrastructure, it translates to more government spending and dependency in a second Obama term, all to somehow be financed with tax hikes on the rich.”) But the left is not about to acknowledge Obama has become reactionary, a throwback to the moldy policies of LBJ and FDR, with virtually no new ideas (other than new things on which to spend your money). So much better to grumble about the speaker, declaring that the speech bombed because he was flat and maybe even depressed about the jobs numbers.

The left will throw Obama and/or his campaign overboard in a flash if they think he might lose (or after the election if he does lose). Better to have a discredited messiah than a discredited political world view. They might not be able this time to prevent Obama’s defeat, but they’ll never let him take liberalism down with him.