Because they don't want democracy to work

It's quite simple and it reminds me of a plumber who was sure -- back in the early days of solar-heated hot water -- the new system wouldn't work.  "I promise you," he said, "it's not going to work." 

Why not?  Because in the end when the system was working, the water was heating, he refused to hitch the system to the house.  Stalked off the job.

That's what Republicans tend to do (again!) if Obama wins.

Vote for Mr. Romney, they say, because if he loses, Republicans will destroy the economy.

O.K., they don’t quite put it that way. The argument is phrased in terms of “partisan gridlock,” as if both parties were equally extreme. But they aren’t. This is, in reality, all about appeasing the hard men of the Republican Party. ...Paul Krugman, NYT

And Republicans will gladly sacrifice the nation in order to defeat Obama.  It sounds impossibly psychotic.  But it's been going on for two years already.

Krugman points to the Des Moines' Register's endorsement of Romney.

The paper acknowledged that Mr. Obama’s signature economic policy, the 2009 stimulus, was the right thing to do. It also acknowledged that Mr. Obama tried hard to reach out across the partisan divide, but was rebuffed.

Yet it endorsed his opponent anyway, offering some half-hearted support for Romneynomics, but mainly asserting that Mr. Romney would be able to work with Democrats in a way that Mr. Obama has not been able to work with Republicans. Why? Well, the paper claims — as many of those making this argument do — that, in office, Mr. Romney would be far more centrist than anything he has said in the campaign would indicate. (And the notion that he has been lying all along is supposed to be a point in his favor?) But mostly it just takes it for granted that Democrats would be more reasonable.

Is this a good argument? ...Paul Krugman, NYT

Ironically, too, the House may have a bunch more Democrats by the end of next week if the polls are correct.  Decent people, legislators, cooperators, hard workers.  Not intransigent radicals preaching mayhem and issuing threats.

... Are we ready to become a country in which “Nice country you got here. Shame if something were to happen to it” becomes a winning political argument? I hope not. By all means, vote for Mr. Romney if you think he offers the better policies. But arguing for Mr. Romney on the grounds that he could get things done veers dangerously close to accepting protection-racket politics, which have no place in American life. ...Paul Krugman, NYT

Conservative humorist PJ O'Rourke once admitted what Republicans have been up to for years.

The Democrats are the party that says government will make you smarter, taller, richer, and remove the crabgrass on your lawn. The Republicans are the party that says government doesn't work and then they get elected and prove it.

That was then (a speech at the Cato Institute).  This is now (during the Obama presidency).  Think of the worst behaviors of the Cosa Nostra and then add the flavor of racism and you've nailed the Republican Party of 1980 to present and -- they hope -- into the future.