Joe Biden told a newspaper that he would not comply with a subpoena to testify in President Trump’s impeachment trial—then sought to clarify his remarks on Saturday.

“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,” Biden told the Des Moines Register editorial board. “The issue is not what I did.”

This is all about a diversion,” Biden added. “And we play his game all the time. He’s done it his whole career.”

Biden’s statement of defiance to the Register drew sharp criticism from some quarters, including a former associate White House counsel under President Barack Obama.

“Terrible answer @JoeBiden,” Ian Bassin tweeted. “Subpoenas aren’t optional. You know better. You should correct record and commit to complying with any lawful subpoena, reserving the right to contest it in court if you believe it to be unlawful. Let Trump tarnish the rule of law; you should defend it.”

On Saturday, Biden appeared to back off his original comments to some degree in a Twitter thread that suggested he might fight any subpoena in court.

“I want to clarify something I said yesterday,” he wrote. “In my 40 years in public life, I have always complied with a lawful order and in my eight years as VP, my office — unlike Donald Trump and Mike Pence — cooperated with legitimate congressional oversight requests.”

Stopping short of denying he would defy a subpoena, he went on to say that he was “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.”

He then tried to shift focus back to the president. “The subpoenas should go to witnesses with testimony to offer to Trump’s shaking down the Ukraine government — they should go to the White House,” he wrote.

Bassin then praised Biden for revising his comments:

“This is what responsible leadership looks like. He said something imprecise that mattered and fixed it because, unlike Trump and his lawless crew, Biden cares about the Constitution and the rule of law. Will Trump’s team now comply w the law?”

The issue of whether Biden has any role to play in impeachment proceedings in the Senate has become a focal point for many Republicans seeking to protect the president. They said Biden and his son Hunter should be forced to answer questions about their activities in Ukraine.

The impeachment process kicked off after Trump spoke to Ukraine president Volodymyr Zelensky about investigating the Bidens and then held back military aid.

Biden himself has repeatedly said he and Hunter did nothing wrong and that he did not speak to his son about official business involving Burisma, the Ukrainian natural gas company on whose board the younger Biden served.

The House of Representatives voted along party lines on Dec. 18 to impeach Trump. The order is expected to be passed to the Senate for a trial in early 2020.