In one scenario, Mr. Collins would have run for a vacancy in the Town of Eden, but had to establish residency there before the general election. (Residents there subsequently held a protest, holding signs that included, “Collins is a swamp monster.”)

As a three-term congressman, Mr. Collins is not a senior member on Capitol Hill, but he gained notoriety in 2016 after he became the first member of Congress to endorse Donald J. Trump.

Last month, federal prosecutors charged Mr. Collins, who sits on the board of Innate Immunotherapeutics, a drug company based in Australia, with providing inside information to his son and others that the company had failed a crucial drug test. His son, his son’s fiancée and his son’s father-in-law all sold shares.

Mr. Collins has proclaimed his innocence and said he had willingly spoken with two F.B.I. agents in April to clear his name when they knocked on his door at 6 a.m., according to the lone television interview he has done since his indictment, with WIVB in Buffalo.

“As it turns out, they don’t read you your rights, they don’t tell you you could have an attorney, they don’t tell you while you’re there,” Mr. Collins said in the interview last week.

“I shared everything from A-to-Z,” he added. “And then at the end of it all, they said, ‘Oh by the way, we have a subpoena for you.’”

Mr. Collins had said last month that he would “fill out the remaining few months” of his term but that it was in the “best interest of the constituents” of the 27th Congressional District for him to suspend his re-election campaign.