The escalating war of words between President Trump and Democratic big-city mayors — brought it to a head by confrontations in Portland and Seattle — is a preview of what's to come in the months leading up to November.

The big picture: Trump is using Democratic mayors as the foils for his law-and-order reelection message, while they've called his deployment of federal agents in their cities "a step short of martial law" and heightened their criticism of the federal response to the coronavirus pandemic.

It's the latest clash between Trump and liberal mayors, who've been convenient contrasts on a host of issues including immigration, homelessness and public health.

What they're saying: Mayors have called for the removal of federal officers, investigations into their tactics, and congressional legislation to restrict their authority to operate in cities.

• "We've been forced to take these extreme actions in the face of unwarranted, and we believe unconstitutional, abuse of federal power," Portland Mayor Ted Wheeler said earlier this week while speaking with other members of the U.S. Conference of Mayors on a press call.
• He added that the "federal occupation of our streets" only heightened tensions with protesters. "Escalation has been met with escalation."
• Seattle Mayor Jenny Durkan called the deployment of federal law enforcement for political purposes "a step short of martial law."

The latest: The administration has since agreed to a "phased withdrawal" of federal troops from Portland, and Washington State officials said on Tuesday that the federal agents who arrived in Seattle last week would be departing.

• “As the President and Secretary Wolf have both made clear, federal law enforcement officers will not leave until the seat of justice in Portland is secure," said White House deputy press secretary Sarah Matthews in a statement.

Yes, but: Despite the federal pullback from Portland and Seattle, mayors are warning of "unprecedented" and "dangerous" use of federal law enforcement as tensions rise across the country.

• The Justice Department has expanded its "Operation Legend" program aimed at combating violent crime into Albuquerque, Chicago, Cleveland, Detroit and Milwaukee.

What we're watching: Albuquerque Mayor Tim Keller said the city will collaborate with federal law enforcement as long as there's a clear understanding of the mission and parameters of those efforts, which are usually laid out in an official agreement beforehand.

• That did not happen with Operation Legend, he said.
• "Contrary to all our other interactions with federal law enforcement, we were given no notice at all," he said.

Go deeper: Trump bends the Department of Homeland Security to his will