For Democrats who might be rooting for Donald Trump, thinking he would be easy to beat in November, I have some advice: Be careful what you wish for.

In his campaign, or rampage, Trump has done more than take a sledgehammer to the Republican Party. He almost seems to be reinventing politics in a way that makes both major parties seem hidebound, sluggish and concerned mostly with self-perpetuation — which, in fact, they are.

When he announced his candidacy, no one outside of Trump’s household dreamed he would be dominating the Republican field with three weeks to go before the Iowa caucuses. Given the way he has set the agenda for the campaign, it’s tempting to call him a master strategist — except I don’t believe he has a strategy. Or needs one.

Instead, Trump is guided by instinct. The whole campaign has been like his stream-of-consciousness Twitter feed or his improvisational jazz-riff campaign speeches. He tests a new theme and gauges the response. If it’s working, he pushes harder; if not, he moves on. Kick out the illegal immigrants and build a wall on the border. Bar Muslims from entry because they might be terrorists. Abolish gun-free zones, even in schools.

Many of Trump’s positions are abhorrent. Many are inconsistent with traditional American values, Republican Party dogma, various articles of the Constitution and Trump’s own views in the past. But substance is, in a way, less important than style. Trump couldn’t possibly do half of what he promises, and probably doesn’t really want to do much of the rest.

The important thing is that Trump, by being transgressive in the way he speaks, gives listeners the license to be transgressive in the way they think. When he rails against “political correctness,” he’s talking about the manners and courtesies that many of us would call being “civil.” But his in-your-face bullying strikes a chord with the large segment of the Republican electorate that is tired of being polite: middle-class, non-college-educated white voters who have not prospered over the last two decades and see demographic change as a threat.

Trump was quick to understand how angry the Republican base is with the party establishment. Vote for us, GOP leaders said, and we’ll stop illegal immigration, repeal the Affordable Care Act, slash spending to the bone, reduce the long-term federal debt and basically stop everything President Obama is trying to do. They failed to deliver — and now someone is calling them on it.

For Trump, saying outrageous things that would end any other politician’s campaign or career is no risk. On the contrary, it’s a necessity. His appeal to primary voters involves a bald-faced appeal to racial and ethnic animus; he gives his supporters permission to bemoan the fact that “they” — Mexicans and Muslims, primarily, but also African-Americans and uppity women — are changing the nation.

Trump’s arena-size rallies have become set pieces in which big, boisterous crowds get to act out their “Make America Great Again” fantasies. If protesters didn’t show up to advocate the Black Lives Matter movement or tolerance toward Muslims, Trump would have to hire actors to play those parts. Antagonists are necessary for the moments of catharsis when interlopers are identified, scorned and physically ejected. It is theater, not politics, a symbolic enactment of the grand purification Trump promises.

The other candidate touching a nerve with the cultural and economic left-behinds — minus the racism — is Sen. Bernie Sanders, the Vermont independent, who is also kind of an un-politician. This is a bad year to rule anything out, so maybe Sanders will win both Iowa and New Hampshire and go on to seriously challenge Hillary Clinton for the Democratic nomination. But if he falls short, the eventual GOP nominee will face a formidable and experienced politician who cannot possibly run as anti-establishment.

If the Republican nominee is Trump, do you believe for a minute he would consider himself bound by the things he said during the primaries? I don’t.

Trump can hardly back away from his categorical pledge on immigration — to expel 11 million undocumented migrants and build a wall along the border with Mexico — so maybe that would energize Latino voters in support of Clinton. But he would do everything possible to lower passions among other loyal Democrats — while stoking them among the new “take back the country” voters he hopes to turn out.

How disgusted is the country with traditional politics and politicians? Democrats had better explore that question — or be surprised by the answer.