Whatever happens, it’s a safe bet the 2012 presidential election won’t go down in history as one for the ages. Barack Obama and Mitt Romney have bickered ad nauseum, but neither has put before voters credible plans for reviving the economy or breaking the choke hold that political polarization has on American democracy.

The choice facing voters, however, isn’t just between the two candidates. It’s also between the parties they represent. And here the choice is easier: Based on its record of political sabotage over the past four years, the Republican Party richly deserves to lose.

America could survive four years of President Romney. But a Romney victory would reward his party’s reckless embrace of ideological extremism and obstructionism. It would vindicate the GOP’s decision to abandon the political center, put partisanship before country, and cater shamelessly to the voters’ darker impulses.

Worst of all, it would give power to a party that hates government so much that it is incapable of governing. A Republican victory would likely mean four years in which the problem-solving capacities of our national government would continue to atrophy.

This is a pretty serious indictment, so let’s be specific.

The next president’s first big challenge will be to keep America from barreling off the fiscal cliff. That would mean higher taxes for everyone and irresponsible cuts in both domestic and defense spending. Letting that happen would fix our debt problem, but in the worst possible way — by plunging our fragile economy into an icy bath of job-killing austerity.

Fiscal politics can’t be divorced from economic politics. We need to fix the debt because we need to fix our economy. Everything else — spurring new investments in growth; overhauling our tax system; reforming entitlements; rationalizing defense spending, improving public education; fixing our immigration mess — depends on putting in place a credible framework for debt reduction as the recovery picks up strength.

Republicans have no serious answer to America’s fiscal dilemma. Their plan to reduce the debt by spending cuts alone is a political fantasy. No self-respecting Democrat would ever go along with it, and plenty of GOP voters would rise in revolt if it actually happened. Yet today’s Republicans have sold their political souls to Grover Norquist, signing blood oaths to never, ever do what Ronald Reagan did repeatedly — raise taxes to close deficits.

Sure, Romney probably didn’t mean it during the GOP primaries when he joined his rivals in rejecting even a 10-1 ratio of spending cuts to tax hikes. Maybe a President Romney would try to broker a bipartisan deal that combines higher revenues and spending cuts. But why would his party, flush with electoral victory, go along?

Democrats might not be in a compromising mood either if President Romney honored his pledge to start undoing Obamacare on day one. Nothing is more likely to trigger a resumption of partisan trench warfare on Capitol Hill, not to mention endless litigation. And if voters were angry at Obama for taking his eye of the economic ball during the great health reform battle, imagine how’ll they feel if Republicans spend the next two years reprising that battle instead of attending to a still-weak economy.

Another urgent task facing the next president will be to get energy and environmental policy back on track. Here again the contrast between Obama’s comprehensive approach and the Republicans’ one-sided demands is stark. Their “drill-baby-drill” mantra would deepen America’s reliance on fossil fuels, especially coal, boost U.S. carbon emissions and retard the development of renewable fuels and clean technologies of all kinds.

In fact, America’s shale gas and oil windfall is a tremendous boon to the U.S. economy. Obama has acknowledged as much, even as some environmental activists and liberals delude themselves into thinking we won’t develop these resources. But more shale gas and oil must be part of a balanced national energy strategy that also puts a price on carbon emissions to drive private investments in energy efficiency and innovation.

Immigration reform is another task that has been deferred too long. Obama has vowed to make it a priority in a second term, but it’s hard to see how the Republicans could build a broad political consensus behind their militantly restrictionist views.

Could Romney, who famously urged illegal immigrants to “self-deport,” pull a “Nixon to China” and embrace a comprehensive reform blueprint that includes a path to legal status for a significant chunk of them? Well, he’s nothing if not flexible when it comes to changing his positions. But why would his triumphant party feel any need to back off of its opposition to “amnesty,” especially if they only won about a quarter of the Latino vote?

Nothing better captures the radicalization of the GOP — and its political costs — than the party’s swing to the right on immigration. The last two GOP presidential nominees supported comprehensive immigration reform, with George W. Bush winning 40 percent of the Latino vote in 2004. Under the influence of Tea Party-infused nativism, the Republicans have burned bridges to these voters and turned themselves into a party of white identity politics.

Their attempts to resurrect the old bugaboo of “welfare dependency” and relentless efforts to delegitimize Barack Obama have not gone unnoticed by black Americans. They wonder why the temperate Obama, who goes out of his ways to avoid rubbing salt in America’s racial wounds, should be regarded by many on the right as some kind of foreigner or “socialist” interloper who wasn’t really born here and therefore is literally un-American. If this isn’t a matter of racial prejudice, what is it?

Presidential elections are opportunities for political accountability and democratic self-correction. For decades after the schisms of the late 1960s, Democrats were punished by voters for having wandered deep into the fever swamps of left-wing ideology. Now it’s the Republicans who have embraced a radical anti-government dogma that is out of step with America’s essentially moderate political ethos.

It’s up to voters, especially independents and moderates, to fortify the pragmatic center by denying Republicans victory.