Most Democrats are happy that Donald Trump’s campaign is stumbling.

But some, looking at the long term, might think that a Trump win next month would be a good thing. Not for the country, they would explain, but for the future of the Democratic Party.

Just like Barack Obama’s win in 2008 hurt Democrats in elections later on, Trump’s victory would be terrible for the Republicans in future elections. Obama’s victory seemed to be the prelude to a long period of Democratic dominance and control of the House and Senate. But it did not last long because Obama’s victory provoked a powerful Tea Party-like response from an angry segment of the public.

These motivated crowds marched to the polls in 2010 and reversed Democratic gains, retook control of Congress, and gained control of the state legislature in North Carolina.

Control of state government, sealed in 2010, enabled Republicans in North Carolina to redraw congressional and state legislative districts to insure their party’s long-term dominance.

The same thing happened in other states.

Most Democrats hope that a Trump loss in North Carolina would help Democrats gain in the U.S. Senate and state legislative races. Still, nobody thinks control of the North Carolina legislature can be returned to Democrats this election.

But, if Trump were to win and become president, he would provoke anti-Trump and anti-Republican voters in the 2018 and 2020 elections, which would be monumental, surpassing even the anti-Obama reaction in 2010.

A little history from the midterm elections shows how the party of the incumbent president fares in those elections.

In the 1994 elections, two years after Bill Clinton won the presidency, Democrats lost 54 seats and control of the House. They lost nine seats and control of the U.S. Senate.

In 2006, two years after George W. Bush won reelection, Republicans lost 32 seats and control of the U.S. House. They lost six seats and control of the U.S. Senate.

In 2010, two years after Barack Obama won the presidency, Democrats lost 64 seats and control of the House. They lost five seats in the Senate and kept control only by a two-vote margin.

In 2014, two years after Barack Obama won reelection, Democrats lost 13 House seats. They also lost nine seats and control of the U.S. Senate.

Arguably then, a Trump win in 2016 would assure Democratic victories in 2018 and beyond.

On the other hand, if Trump continues his downward spiral and Hillary Clinton wins the presidency, history shows what could happen in 2020. No party in recent political history, except the Democrats’ run of five straight presidential election victories with Franklin Roosevelt and Harry Truman, has been able to win four presidential elections in a row. After two or three terms of one party in the White House, the electorate wants a change.

Therefore, in 2020, a President Hillary Clinton running for re-election would face angry voters rising up again against the establishment and demanding change. Assuming Republicans nominate a reasonably sane candidate, their enthusiasm and the anger of the Clinton haters would make their nominee the overwhelming favorite to beat Mrs. Clinton’s bid for re-election.

With the wave of enthusiasm that could bring their 2020 presidential victory, Republicans would have a good chance to sweep the state legislative races as they did in 2010, opening the door for another round of gerrymandered redistricting that would ensure their control of the U.S. House and state legislatures for many more years to come.

It is just one more reason why loyal Republicans, with an eye on the future of their party, might hope for a big Democratic victory next month.

D.G. Martin hosts “North Carolina Bookwatch,” which airs on UNC-TV.