He may rue that decision next Tuesday. Whether the midterm elections are a tidal wave that sweeps Democrats out of power on Capitol Hill or simply result in major losses for the president’s party, one thing is clear: The stimulus will play a major role in determining the outcome. The legislation has not kept the unemployment rate below 8 percent, as the White House promised — but it has been an electoral boon to Republicans, and an albatross around the necks of many Democrats who voted for it. It might have been a different story had Obama handled the stimulus differently. In January 2009, Republicans were running scared — still reeling from the thumping they received in the past two elections, and afraid to so much as criticize the new Democratic president with stratospheric approval ratings. In these circumstances, the president could have easily co-opted the GOP by making it a partner in crafting the stimulus. He could have told Republicans: Take half of the money and use it for tax relief, spending, or both. Indeed, Republicans introduced several alternative stimulus bills that cost half as much as Obama’s (“twice the jobs at half the cost” was the GOP mantra). Had Obama really wanted to be the first “post-partisan” president, he could have incorporated one of these alternatives into his final stimulus legislation.

If Republicans had gone along, they would have had to defend the stimulus for the next two years. If they had refused, they would have been in no position to criticize a bill that they had turned down the opportunity to help shape. If the stimulus worked, both sides could have taken credit. And if it failed, reaching out to Republicans would have inoculated the president from the resulting criticism. Had he given them half the booty, they would have shared half the blame.

Would Republicans have accepted hundreds of billions in new government spending in exchange for including pro-growth tax relief and other GOP proposals? The offer would likely have split the party, with a significant number supporting the bill. The grass-roots movement for fiscal discipline had not yet been born, and many of the same Republicans who voted in favor of the “Bridge to Nowhere” would have gladly compromised with the popular new Democratic president. The stimulus would probably have passed with significant bipartisan support, instead of near-unanimous Republican opposition.

But Obama was not interested in compromise. He decided to go it alone. He picked off a few easy GOP votes and rode roughshod over the rest of the Republicans to pass a maximalist bill over their objections. That may have seemed like a good idea at the time. But looking back now, a week from the midterm elections, the wisdom of his approach is hard to discern.

The stimulus united Republicans for the first time in opposition to the president. It gave rise to the Tea Party movement that has fundamentally transformed the nation’s political landscape in the GOP’s favor. It changed Obama in the eyes of millions of Americans from the first “post-partisan” president into what many now perceive as (to quote Obama himself) “the same old tax-and-spend liberal Democrat.” And his subsequent decision to ram Obamacare through Congress over unanimous Republican opposition sealed this impression, which voters will carry into the voting booth next Tuesday.

Almost two years later, the president still doesn’t get it. In a recent New York Times profile, Obama says the lesson of his political setbacks is that “you can’t be neglecting of marketing and PR and public opinion.” Obama’s problem was not marketing and PR — it was his insistence on imposing big government liberalism on Americans against their will, and his failure to anticipate the blowback this approach would produce.

Will Obama figure this out after next Tuesday? Even if he does, it will be too late. Should next week’s elections turn out the way most pollsters predict, Republicans will have no incentive to compromise with Obama on expanding the size of government. To the contrary, newly elected Republicans will arrive with a clear mandate to cut spending and restore fiscal discipline. If they fail to follow this mandate, they will likely have very short tours in Washington.

In January 2009, Republicans were on their heels, ready to compromise with the president. In January 2011, Republicans will likely be energized and emboldened to roll back Obama’s most egregious initiatives. The president was right. Elections do have consequences.

Marc A. Thiessen is a visiting fellow with the American Enterprise Institute and writes a weekly column for The Post.