Presidential candidates proclaim that there never has been an election as important as this one.

"The challenges we face now are direr than any time in our modern history," said Sen. Bernie Sanders, a Vermont Democrat.

"This is not a typical election," said Sen. Ted Cruz of Texas, a Republican candidate. "I think the stakes have never been higher." Sure, no candidate is going to say this election is no big deal. But more important or direr than 1932, in the midst of the Great Depression? Or 1940, on the verge of World War II? Or 1980 or 2008? In fact, the stakes for the two U.S. political parties could be that great. Consider the likely ramifications of a 2016 defeat for Democrats and Republicans.

If the Democrats lost the presidency, it's a near certainty that the party wouldn't regain control of the Senate or the House, where Republicans already enjoy comfortable margins. Republicans could control in excess of half the governorships and state legislatures in 2017.

And Republican appointees are a majority on the Supreme Court, which after some liberal-leaning decisions on the Affordable Care Act and gay marriage, will likely tilt conservative again.

Such a scenario would make Republicans even more powerful than when they held all the levers of power from 2003 until 2007: Then, they didn't control as much on the state level, and in Congress there still were moderate to liberal party lawmakers, such as Arlen Specter and Lincoln Chafee, who often voted with Democrats. (Both subsequently became Democrats.) The Democrats, who consider themselves the governing party, would be in their weakest position since the 1920s.

advertisement | advertise on newsday

Moreover, they would be strikingly short of younger fresh faces -- who is the Democrats' equivalent of the 45-year-old Paul Ryan? In the Senate, Harry Reid, 75, has anointed Chuck Schumer, who will be 65, to replace him as Democratic leader. In the House, Nancy Pelosi, for more than a decade a powerhouse leader, is 75; the No. 2 Democrat, Steny Hoyer, is 76.

The party would struggle to find a way to highlight younger up-and-comers: senators such as Michael Bennet of Colorado (50), New York's Kirsten Gillibrand (48) the likely next Maryland senator, whether Chris Van Hollen (56) or Donna Edwards (57). For the House, there is Joe Kennedy of Massachusetts (35); or promising candidates such as 44-year-old Lon Johnson, former state party chairman, running in Michigan's Upper Peninsula.

The consequences of a loss would be even more cataclysmic for the Republicans, threatening a party split. It would be the sixth of the past seven elections in which Republicans have lost the popular vote. That has never happened before.

Sign up for The Point

Go inside New York politics.

There are bitter schisms within the party. Ryan is likely to replace John Boehner this week as House speaker, but there's already betting on how long his honeymoon with rival factions within the party will last. That, along with a divisive presidential contest, foreshadows a blood bath if the party loses next year.

If an establishment Republican -- Jeb Bush, John Kasich or Marco Rubio -- were to win the nomination and lose the election, the right wing would explode. It's an article of faith among the movement right that the establishment needs to be decimated before the party can rebuild. A defeat with an establishment candidate would ignite those passions.

If one of the outsider candidates -- Donald Trump, Ben Carson or Cruz -- led the ticket and was routed by a Democrat, the establishment would contemplate ways to diminish the role of those they consider the "nuts" in the party.

Unlike with the Democrats, the Republicans do have some younger figures angling for leadership: Ryan, Cruz or Rubio. But none transcends these fissures.

And in the unlikely event Trump were to won? Republicans and Democrats both might have nervous breakdowns.

advertisement | advertise on newsday

Albert R. Hunt is a Bloomberg View columnist.