MINNEAPOLIS (AP) — The conflict on which President Donald Trump thrives arrived in Minnesota well ahead of his touchdown in the liberal heart of a state he craves to win next year.

Trump traded Twitter insults with the Minneapolis mayor over who should pay more than $500,000 in security costs for Thursday’s rally at a downtown arena. He denounced Jacob Frey as a “Radical Left” lightweight and blasted the Democrat for a police policy banning officers from wearing their uniforms in support of political candidates. He sprinkled in a reference to his favorite foil — the city’s Rep. Ilhan Omar — just for good measure.

“Yawn,” Frey tweeted back. “Welcome to Minneapolis where we pay our bills, we govern with integrity, and we love all of our neighbors.”

It was just a warm-up to Trump’s first campaign rally since being engulfed in the swirl of an impeachment investigation. The event is expected to carry extra partisan punch. Trump lands in Minnesota as polls show Americans’ support for impeachment and for removing him from office have ticked up in the weeks since House Democrats launched an impeachment investigation.

While his GOP allies have launched a campaign to reverse the trend, Trump’s self-defense may be the best preview of how he intends to fight back in the weeks ahead.

“He needs to be able to show right now, given all of this impeachment stuff, that America is rallying to his defense. And I don’t think that is going to be the optic that’s created,” said Ken Martin, the state Democratic chairman.

Both sides are tuned in to the symbolism of the moment. The rally at Target Center– the city’s basketball arena– is expected to draw thousands of passionate supporters as well as protesters outside. Trump will be joined by Vice President Mike Pence, who had a separate schedule of appearances in the state this week.

Minneapolis is a difficult place for the president to try to bask in the glow of support. Trump won just 18 percent of the vote in the dense, diverse and liberal congressional district where he’s staging his rally.

But the venue serves another purpose: The district is now held by Omar, the Somali-American lawmaker Trump often holds up as a symbol of the liberal shift in the Democratic Party. It’s a message viewed as racist by some. He has tweeted that Omar should “go back” to her home country if she wants to criticize the U.S., and the comments are sure to inflame passions on both sides.

The strategy is at the heart of Trump’s plan to hold on to the Rust Belt and become the first Republican presidential candidate to carry Minnesota since Richard Nixon in 1972. Trump fell fewer than 45,000 votes short of beating Democrat Hillary Clinton statewide. He’s had staff in the state since June, and they have been busy building a network to turn out supporters next November.

The campaign needs to pump up Trump’s support in the rural and suburban areas he carried in 2016 to overcome Democratic strength in Minneapolis, St. Paul and some other cities, plus suburbs that swung Democratic in 2018.