Politics is a funny thing.

It's not logical or linear. And it's rarely predictable.

When one party is on top, it can seem like it'll be there forever. Then, in the blink of an eye, it's pushed from power and ridiculed as ideologically exhausted -- often regardless of how successful it has been. How many times has liberalism or conservatism been declared dead in the past 50 years, only to romp in the next election cycle? The Republican Party was shattered in 1976. In 1980, it was the Democrats' turn.

The starkest example of this is taking place in New York City. New Yorkers learned their lesson about liberalism in the late 1980s and early '90s, right? Voters would never again go for a Kumbaya candidate or for hands-off police policies. Yet Democrat Bill de Blasio is leading in the mayoral race by more than 40 points against a Republican who played a major role in the city's revitalization. What got de Blasio there? Attacking the policing that saved the city. Even when stories about his work with Marxist Sandinistas broke, de Blasio's polling numbers still rose.

The death of the Republican Party is all the talk. There is a fatal schism, the line goes, between mainline Republicans and populist tea partyers.

At this very moment -- days after the government shutdown -- this argument sounds about right, obvious almost. How can blue state Republicans survive Sen. Ted Cruz (R-Texas) and his debt-ceiling tactics?

The answer in a word is Democrats. For as doctrinaire as Republicans are alleged to be, Democrats are more so. Whatever happened to the conservative Democrat? He is nonexistent in government today.

The reason is the Democrats' existential reliance on public service unions to re-elect them. Step out of line by opposing increased public spending or pension benefits, and a well-funded primary will come your way. New York's Working Families Party, an amalgam of union and other left-wing interests, has perfected this approach. It dictates the agenda among New York Democrats.

The Republican Party is a beaten puppy, with its tail squarely between its legs. But it's the only party addressing fiscal issues realistically. That will ensure its rebound, as preposterous as that might sound today.