TIPTON, Iowa — Joseph R. Biden Jr., expanding on his remarks a day earlier that he would not comply with a subpoena to testify in President Trump’s impeachment trial in the Senate, wrote on Twitter on Saturday that there would not be “any legal basis” for such a subpoena.
But speaking with reporters on Saturday, Mr. Biden stopped short of vowing to fight a subpoena if one were ultimately issued. “I would honor whatever the Congress in fact legitimately asked me to do,” Mr. Biden said after a town-hall-style event in Tipton, Iowa.
Asked if he would challenge a subpoena in court if he believed he had no facts to provide that would be relevant, he responded: “The answer is, I don’t think that’s going to happen to begin with. Let’s cross that bridge when it comes.” He added that he would abide by “whatever was legally required of me.”
The result was a sometimes confusing attempt to address a hypothetical situation that Mr. Biden criticized himself for drawing attention to in the first place, despite his own pleas to the news media to focus on Mr. Trump and his behavior in office.
Mr. Biden wrote on Twitter that over the course of his decades-long political career, he had “always complied with a lawful order,” and that in his two terms as vice president, his office had “cooperated with legitimate congressional oversight requests.”
Mr. Biden’s further explanation on Saturday began with a series of tweets in the morning. He wrote that he wanted to “clarify” comments he had made on Friday, when he met with the editorial board of The Des Moines Register, whose endorsement in the Iowa caucuses is highly sought after by presidential candidates.
Mr. Biden was asked by The Register whether he stood by previous comments that he would not comply with a subpoena to testify in the impeachment trial. He said he did, and explained that complying with a subpoena and testifying would effectively allow Mr. Trump to shift attention onto Mr. Biden and away from the president’s own conduct.
“The reason I wouldn’t is because it’s all designed to deal with Trump doing what he’s done his whole life: trying to take the focus off him,” Mr. Biden told the newspaper. “The issue is not what I did.”
On Saturday, Mr. Biden elaborated on Twitter: “I am just not going to pretend that there is any legal basis for Republican subpoenas for my testimony in the impeachment trial. That is the point I was making yesterday and I reiterate: this impeachment is about Trump’s conduct, not mine.”
Speaking to reporters in Tipton, Mr. Biden said he had “no firsthand knowledge” about the accusations against Mr. Trump, so there would be no rationale for calling him as a witness.
The House impeached Mr. Trump this month over his campaign to pressure Ukraine to investigate Mr. Biden and his son Hunter Biden. In the aftermath of Mr. Trump’s impeachment, the Senate majority leader, Mitch McConnell of Kentucky, and the minority leader, Chuck Schumer of New York, have been at odds over proceedings for a trial, in part because of Mr. Schumer’s request to call Trump administration officials for testimony at an impeachment trial.
House Speaker Nancy Pelosi of California has said she will not formally send the articles of impeachment to the upper chamber until she has assurances that the trial will be conducted fairly.
As he spoke to reporters in Tipton, Mr. Biden seemed to fault himself for entertaining the hypothetical of whether he would comply with a subpoena — and creating a story line in the news media that continued on Saturday. Mr. Biden observed that “this is going to be the news today” and added, “I’m criticizing myself.”
“I shouldn’t even have answered the question,” he said. “Because in answering the question, now there’s going to be another round. We’re not talking about: What did Trump do?”
Emily Cochrane contributed reporting from Washington.