Republicans could compel Hunter Biden to testify if Democrats succeed in calling former national security adviser John Bolton to be a witness in the Senate impeachment trial.

So said Sen. Ted Cruz in an interview Thursday with the Washington Examiner, shortly after he was sworn in by Chief Justice John Roberts for the Ukraine impeachment trial set to begin next week. The Texas Republican made it clear that, while no decision has been reached on whether new witnesses would be called, he believed the Republican Senate majority would support Trump's legal team getting to call at least an equal number of its own witnesses, potentially including 2020 Democratic front-runner Joe Biden's son, if Democratic House managers for the trial are allowed to call in further people to testify.

“If additional witnesses are called, at a minimum we should respect the principle of reciprocity,” said Cruz. “So, if the prosecution is allowed one witness, the White House ought to be allowed at least one witness. If the prosecution is allowed two witnesses, the White House ought to be allowed two witnesses.”

The Republican said: “That would mean, as a practical matter, if the House managers called, for example, John Bolton, that the White House defense team could call as a witness, say, Hunter Biden.”

The two articles of impeachment passed by the House charge the president with soliciting Ukraine's help to interfere in the 2020 election while withholding military aid and with obstructing the congressional investigation into the matter.

Bolton's former aide, Fiona Hill, testified that Bolton opposed the alleged Ukraine pressure campaign, saying he wanted no part of what he described as a "drug deal." And Bolton, who left the White House in September, announced last week he is willing to testify in the trial. The GOP would be keen on hearing from Biden’s ethically-plagued son about his dealings in Ukraine and his lucrative position on the board of the Ukrainian energy company, Burisma, in response.

Cruz, 49, is a conservative stalwart who clashed with Trump in 2016’s brutal GOP presidential primary, but he's been a defender of the president against what he called the Democratic “show trial” in the House, vowing the Senate wouldn't become a “kangaroo court.”

He said the first order of business next week would be voting on a schedule similar to the one in President Bill Clinton’s impeachment trial two decades ago, including a “phase one” with opening arguments from Democratic House managers for 24 hours over two days, then opening arguments from Trump’s defense team for up to 24 hours over another two days, followed by written questions to the legal teams submitted through and read by Justice Roberts. Only then would more possible witnesses be discussed, if Republicans get their way, although Democrats want to force the vote early next week.

Cruz wasn't sure the required 51 senators would want to hear additional witnesses after each side made its case.

“I don’t know which way that vote will go,” Cruz said. “If the Senate goes down the road of additional witnesses, it needs to be fair and even-handed and respect due process."

But he said exactly who gets selected shouldn’t be up to the senators.

“That’s a determination for the House managers on the prosecution side and a determination for the White House defense team on the defense side,” Cruz said.