Iowa’s U.S. senators said they are unsure of the constitutional validity of holding an impeachment trial for former President Donald Trump, who was impeached last week, just seven days before leaving office.

An impeachment trial looms over the U.S. Senate for the second time in a year, but this trial would be unique among the history of the rare practice because Trump is no longer president.

In an interview with The Daily Iowan on Thursday, Sen. Joni Ernst, R-Iowa, said she doesn’t believe holding the trial would be constitutional. A Congressional Research Services report found that while the text is “open to debate,” the report states that most scholars that have closely examined the question have concluded that Congress has the authority to impeach officials that no longer hold office.

“My question is, and believe me, we have legal scholars going back and forth on this, is can you actually convict a private citizen?” Ernst said. “President Trump today is no longer president…And so that’s where a lot of consideration will have to flow down to is that, are we going to start using this as a vengeance tool against former presidents?”

The U.S. House of Representatives voted 232-197 to impeach Trump on Jan. 13 for incitement of an insurrection that left five people dead. On Jan. 6, pro-Trump rioters breached the Capitol after Trump encouraged the crowd of thousands to march on the Capitol. Ten Republicans joined House Democrats in the measure.

House Speaker Nancy Pelosi can now send the article of impeachment to the Senate at any time, and the Senate would have to immediately begin the trial, though she hasn’t offered a timeframe of when she plans to deliver the article.

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Though the primary purpose of an impeachment trial is to remove the president from office, the Senate can also choose to bar a convicted president from holding federal office again and withhold certain benefits afforded to former presidents.

Ernst, who has criticized Trump in the aftermath of the riot at the Capitol and said he bears some responsibility for the attack, didn’t say whether she would vote to convict Trump in a Senate trial.

She said that voters should decide Trump’s ability to hold future office, and that she doesn’t think voters have an appetite for another four years of a Trump presidency.

“Even if this former president should choose to run again, he would have to face the voters,” she said. “And I don’t know that there would be an overwhelming amount of support after the actions of January 6.”

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All of Iowa’s delegation — both Republican senators, three Republican representatives and one Democratic House member — voted down the objections to electoral college results on Jan. 6 after the insurrection.

Sen. Chuck Grassley, R-Iowa, was less certain about the legality of holding a trial to convict Trump, but he said in an interview with The Daily Iowan on Thursday that he had questions about whether it is constitutional.

“It’s one thing, according to the constitution, to impeach a president, but can you impeach a citizen?” he said. “Because now it’s not President Trump, it’s citizen Trump.”

Grassley declined to say which way he would vote in a Senate trial, but he said he would listen to the testimony and act as an impartial juror.

Referencing President Biden’s inaugural address, Grassley said he doesn’t think an impeachment trial would bring the unity that Biden called for during the speech.

“I don’t think that act would be unifying the country, but I would hope that we would move forward,” he said. “What I hope to do is help President Biden where I agree with him. And I think there’s a lot of areas where I agree, I can help him get his agenda through.”

During the impeachment proceedings on Jan. 13, Iowa’s three Republican representatives voted against the measure, while Democratic Rep. Cindy Axne of Iowa voted for it.

In an interview on Thursday, Axne said she thinks the Senate is capable of holding the trial. She said Trump’s rhetoric on Jan. 6 and through his entire tenure as president inspired the Capitol riot and that Congress should hold him accountable.

“I think we absolutely can,” Axne said of the Senate’s ability to convict a former president. “I’m not exactly sure on all of the framework around it. We would not have done it in the timeframe that we did if we had known that it wasn’t something that could actually be acted on by the Senate.”