(CNN) President Donald Trump understands what got him elected -- a willingness to throw caution and decorum to the wind and to assail what his supporters see as rampant political correctness.

On Thursday night, when he mocked the #MeToo movement as his tour targeting red-state Democratic senators hit Montana, he showed that he thinks the same approach will stave off a GOP midterm election meltdown that could severely constrain his presidency.

The President made his high-risk gamble at a raucous rally as he renewed his attack on Democratic senator and possible 2020 White House candidate Elizabeth Warren and her claim to possess Native American heritage.

He said that if the pair ever clashed in a presidential debate he would give her a DNA test to identify her ancestry.

"We will take that little kit and say -- but we have to do it gently. It's the 'Me Too' generation, so we have to be very gentle. And we will gently take the kit and slowly toss it, hoping it didn't hit her and injure her arm. Even though it weighs only 2 ounces," Trump said.

"And we will say we will give $1 million to your favorite charity, paid for by Trump, if you take the test and it shows you are an Indian."

Trump's comment immediately distracted attention from a speech designed to torch Sen. Jon Tester, one of a string of Senate Democrats facing tough re-election races in states Trump won with thumping majorities two years ago.

It set up the equation that prevailed for much of 2016 -- with Trump adopting a position many people may see as extreme or offensive that causes mainstream media outlets to cry foul. In the process, Trump again became the scourge of liberal, inclusive values and the potential champion of millions of Americans who see such coverage as exactly the kind of fretting political correctness by coastal elites that drew them to the ultimate outsider candidate in the first place.

But while Trump's willingness to blast taboos helped him in 2016, there is no guarantee it will work in the midterms. While it may be popular with his base in the heartland, he's already doing poorly among female voters who could be vital to tight races in suburban districts.

Since he was elected, the #MeToo movement has reshaped perceptions of acceptable male behavior in the media, show business and the workplace. Trump is one of the few public figures facing accusations of harassment who has not been felled. Trump has denied all accusations against him.

So his decision to attack the #MeToo movement is a considerable risk -- one that Warren recognized by quickly responding to his tweet, linking his remarks to the political storm over the separation of migrant families who illegally cross the southern border.

"Hey, @realDonaldTrump: While you obsess over my genes, your Admin is conducting DNA tests on little kids because you ripped them from their mamas & you are too incompetent to reunite them in time to meet a court order. Maybe you should focus on fixing the lives you're destroying," she tweeted Thursday.

Still, while Democrats believe they have an opening, Trump is betting on his method. After all, the mantra first coined by then-first lady Michelle Obama in 2016 -- "when they go low, we go high" -- didn't stop him from becoming President.

It may also be no coincidence that the #MeToo swipe came on the day the White House announced the appointment of Bill Shine, who traveled with Trump to Montana as deputy chief of staff for communications. Shine resigned as a top Fox News executive last year after being accused of covering up a string of sexual harassment allegations.

Classic campaign Trump

Trump's rally on Thursday was a classic display of virtuoso demagoguery and hardball populism that has already been aimed at red-state Democrats like Sens. Joe Manchin in West Virginia, Joe Donnelly in Indiana and Heidi Heitkamp in North Dakota. Missouri's Claire McCaskill and Florida's Bill Nelson are on deck.

"Jon Tester may say one thing in Montana, he does the exact opposite when he goes to Washington," Trump said at a rally in Great Falls, cranking up his cultural, ideological and personal attack machine.

The President accused the two-term senator of voting down the line with liberals on issues of Obamacare repeal, immigration, abortion and tax cuts, grouping him with GOP hate figures like Rep. Nancy Pelosi of California, Sen. Chuck Schumer of New York and Rep. Maxine Waters of California.

"You wouldn't think he would play very well out here -- how did he get elected? You can right that wrong in November," Trump told his adoring crowd. Tester's campaign later noted that his opponent, Republican Matt Rosendale, is originally from the East Coast.

As usual, the President appeared with and praised the local candidate. But Trump's red state blitzkrieg, early by midterm election standards, is really all about him -- as his calculated reference to the #MeToo movement showed.

His appearances highlight the unknowns that will decide whether Democrats can stave off major losses in a tough slate of re-election races, probably the height of their hopes in the Senate, even as they eye a good chance to take back the House.

The first and most important question -- one Trump frequently raises during his travels -- is whether he can defy historic omens and re-create robust turnout from his most loyal supporters that would mirror his stunning 2016 race and help lift Republican candidates.

Such is his toxicity among Democrats and independents, it also possible his appearances could drive up turnout among liberal base activists, female voters who oppose him and swing voters as well.

A related issue is whether Trump can transfer his magnetic popularity and unshakable bond with his base to less charismatic and idiosyncratic GOP candidates. Presidents, from Ronald Reagan to Barack Obama -- who by definition are usually the most talented and inspiring orators in their parties -- have often found that their reflected glow has limited appeal in midterm races.

Another test will be whether Trump's omnipresent national profile can squelch Democratic senators with strong local appeal and independent profiles like Tester, a farmer from the tiny north country township of Big Sandy who has his own populist brand, and West Virginia's Manchin, who has long surfed political waves that have swept his state to the right.

While rallies allow Trump to get out of Washington and do what he loves most -- improvise before a crowd and bask in the adulation of the campaign trail -- it's unclear how much these high summer events matter, apart from as a warm-up for the fall campaign.

"It's still early July. The election is in November," said Jeremy Johnson, a professor of political science at Carroll College in Helena, Montana.

"The effects will dissipate over time. A rally in October is probably more meaningful than any rally in July," Johnson said, though he noted that Trump's appearance would certainly draw enthusiasm from supporters he needs to turn up in November.

The dilemma of red state Democrats

Rallies like the one on Thursday also showcase a November strategy that combines sweet spot issues like immigration, tax cuts, the booming economy and attacks on kneeling NFL players with nostalgic reminiscences of his 2016 campaign that Trump loves and exaggerated and often distorted assessments of his record.

Tester and colleagues like Donnelly and Heitkamp well know the straddle required of Democratic senators in conservative territory, who face the conundrum of voting with the majority opinion in their states or with their national party.

As he hopscotches Senate battlegrounds, Trump incessantly tears at that dilemma.

The discomfort of red state Democrats torn between their own political interests and those of the national party has been multiplied by the sudden detonation of a Supreme Court battle in the middle of a midterm election campaign -- and Trump is not wasting his golden chance.

"If you tune in Monday at 9 o'clock, I think you're going to be extremely happy," he said, teasing his crowd on Thursday about his nominating announcement next week.