What’s the worst-case scenario for Republicans in November? Maybe victory.

A Republican takeover of the Senate is somewhere between plausible and very likely. (If you want more exact predictions, you have to provide a less volatile political climate.) So for argument’s sake, let’s assume Republican candidates roll to victory from Alaska to North Carolina. The Democrats’ 54-46 Senate majority is supplanted by a narrower Republican majority, with Kentucky Republican Mitch McConnell or someone of nearly equal skill installed as majority leader.

The Republicans would then control both the House and the Senate. In the Senate, the most enthusiastic partisans in the new majority would be eager to dispense with the filibuster on legislation, allowing bills to pass on party-line Republican votes. Let’s assume that happens, too.

What exactly would they do with these newfound powers?

They wouldn’t pass a jobs bill because they don’t want President Barack Obama to gain credit for an improving economy. Besides, they’ve convinced themselves that jobs bills don’t work — at least until a Republican occupies the White House.

What about health care legislation? Jonathan Bernstein parses the prospects on his blog. According to a CBS News poll in January, only 34 percent of Americans support repealing Obamacare; it would be a nonstarter even if the health care and insurance industries weren’t already too far down the Obamacare road. If Republicans took the plunge to create legislation, the real-world impacts of their proposals would be scored by the Congressional Budget Office and outside policy groups. It’s hard to imagine what Republicans could devise that would satisfy their ideological needs without undermining health security for millions while increasing the deficit. There’s a reason they keep talking about health care but never get around to doing anything.

How about immigration? Senate legislation drafted by Republicans would look nothing like the bipartisan immigration bill passed by the Senate last June. Senate Democrats would have little incentive to support a vastly more conservative bill, which would rely even more on employment enforcement and militarization of the border while offering far-less-generous terms to undocumented immigrants. Under such circumstances, House Democrats would surely abandon House Republicans to their own devices, as well.

Without Democratic votes, the House cannot pass anything more comprehensive than an immigration crackdown. The fate of the 11 million undocumented immigrants in the U.S. would be unresolved at best. The political failure would be a fiasco, further undermining Republicans among Hispanic and Asian voters while simultaneously opening the door to another round of nativist big-talk among Republican presidential hopefuls. (The U.S. Chamber of Commerce would express its heartfelt disappointment, then funnel millions of dollars to Republican incumbents.)

The party’s internal conflicts would all be exacerbated by a Senate takeover. Imagine, for example, how much leverage a narrow Republican majority would grant to Senator Ted Cruz — and the chaos that could ensue.

In its current incarnation, the party is more or less an anti-tax lobby grafted to a Sons of the Confederacy chapter. Genuine areas of policy consensus among Republicans are few — spending cuts for the poor, tax cuts for the rich and promotion of incumbent dirty energy industries at the expense of Obama’s green agenda. None of these is popular. (Although in coal and oil states the energy reversal would be welcome. Keystone, too, if its construction is not already underway in 2015.) All would face probable Obama vetoes.

What’s left? Entitlement reform? The Republicans’ elderly base is not eager for changes in Medicare or Social Security. That leaves culture warrior stuff, mostly. New abortion restrictions, perhaps? One last lunge against gay rights? Not much electoral magic there.

The party’s capacity to please its right-wing cultural base, its anti-tax, anti-regulatory donor base and a slim majority of American voters is almost nonexistent. Democratic control of the Senate has shielded Republicans both from their own divisions and from the unpopularity of their causes.

Indeed, it’s possible that the Boschian hellscape over which John Boehner presides in the 113th Congress could actually get uglier and more bizarre if Republicans win the Senate in the 114th. I’m not sure even these Republicans deserve that.

(Francis Wilkinson is a member of the Bloomberg View editorial board. Follow him on Twitter.)

Photo: Republican Conference via Flickr