While President Trump is bracing for an impeachment fight in Washington, back home in New York, his friends and allies are grappling with challenges of their own.

Chris Collins of Buffalo was the first member of congress to endorse Mr. Trump for president in 2016. Mr. Collins held up their shared business backgrounds as the reason. But then last week, Mr. Collins resigned his seat and pleaded guilty to insider trading charges.

The city of Buffalo is in Erie County, where there is a contentious election for county executive. It’s being seen by some as an early barometer of voter attitude in the Rust Belt heading into the presidential election season. The candidate running on the Republican Party line, Lynne Dixon, said that she voted for Mr. Trump in 2016 but that it was too early to say if she would vote for him again, according to The Wall Street Journal.

Staten Island is the only county in New York City that Mr. Trump won in the 2016 general election. And Representative Max Rose, a Democrat who represents the area, was one of the few people in his party to resist supporting an impeachment inquiry of Mr. Trump. Was he fearful of a backlash from voters? At a town-hall meeting with constituents last week, Mr. Rose announced he would support the inquiry. “He was greeted with a hearty round of applause,” a colleague wrote.

In Manhattan, Mr. Trump’s accountants were ordered by a federal judge to turn over eight years of his personal and corporate tax returns, as part of a criminal investigation by the Manhattan district attorney. Mr. Trump’s lawyers had argued that a sitting president was immune from such investigations. But Judge Victor Marrero rejected the argument, writing that it was “repugnant to the nation’s governmental structure and constitutional values.” Mr. Trump’s lawyers immediately appealed the ruling. An appeals court agreed to temporarily delay enforcement of the subpoena while it considers arguments in the case.