While he still says impeachment is too extreme, Sen. Rob Portman readily acknowledged Monday that President Donald Trump should not have asked Ukraine or China for help investigating former Vice President Joe Biden. And the Ohio Republican also undercut key factual elements of Trump's explanation of his actions.

Risking a wrathful tweet-storm or worse from President Donald Trump, Ohio Sen. Rob Portman said Monday that Trump should not have asked Ukraine or China to investigate former Vice President Joe Biden and his son Hunter.

"The president should not have raised the Biden issue on that call, period. It’s not appropriate for a president to engage a foreign government in an investigation of a political opponent," Portman said, referring to a July 25 conversation between Trump and Ukraine President Volodymyr Zelenskiy that is at the center of House Democrats' impeachment inquiry. Trump later called on China to conduct such a probe, too.

"I don’t view it as an impeachable offense," Portman said. "I think the House frankly rushed to impeachment assuming certain things" that haven't panned out yet, said Portman, who as a House member voted exactly 21 years ago to impeach President Bill Clinton.

Portman did express openness to an investigation of Trump by a bipartisan group such as the Senate Intelligence Committee. "Everything should be looked at," he said, including accusations that the FBI was politicized in 2016 to go after Trump.

The Cincinnati Republican became the fourth GOP senator to break ranks by criticizing Trump, joining Mitt Romney of Utah, Ben Sasse of Nebrasks and Susan Collins of Maine. Just five days earlier, Trump had praised the Ohio senator for backing him up, saying "there’s nobody more honorable than Rob Portman of Ohio."

Portman, speaking after attending the 4th Annual Ohio Defense Forum, hosted by the Dayton Development Coalition in Columbus' Westin Great Southern Hotel, also undercut key elements of Trump's defense:

• He disputed Trump's characterization of an ousted Ukrainian prosecutor as an aggressive battler of corruption, whom the president asserts was fired because he was digging into the Bidens. Portman was part of a bipartisan group of senators who wrote a letter to the president of Ukraine in 2016 seeking reforms in the prosecutor's office; Monday, Portman said the senators believed the prosecutor wasn't doing nearly enough to root out corruption — not that he was doing too much.

And the Biden issue never came up in that 2016 context, Portman said: "That didn’t even enter into our calculus as far as I know, one way or the other. It certainly didn’t into mine. Because that was something that nobody was even talking about.”

The letter, also signed by Ohio Democratic Sen. Sherrod Brown, came a couple of months after Vice President Joe Biden threatened to cut off a loan guarantee to Ukraine — a move Biden says was motivated by the concern of U.S. officials and others about Ukrainian corruption.

Get the news delivered to your inbox: Sign up for our politics newsletter

• Although Portman confirmed that Trump cited a lack of help from European nations as a reason for holding up aid authorized by Congress for Ukraine, the senator said he never heard that assertion until he spoke to the president personally on Sept. 11, when the aid was released. Earlier conversations with Vice President Mike Pence, Secretary of Defense Mark T. Esper and other Trump administration officials turned up no reason for the hold-up, said Portman, co-founder and co-chairman of the bipartisan Senate Ukraine Caucus.

Democrats say Trump delayed the $391 million to pressure Zelenskiy to investigate the Bidens and a discredited conspiracy theory about the 2016 U.S. presidential election involving Ukraine.

• Portman said “it may have been inappropriate” that Trump offered the services of U.S. Attorney General William Barr and the president’s personal attorney, Rudolph Giuliani, to help the Ukrainians in the twin probes.

• When Portman was asked if the Bidens did anything wrong in Ukraine, he replied: “I honestly don’t know. I would not be prepared to say that, that they did anything wrong.”

Gov. Mike DeWine, the titular head of Trump's re-election campaign in Ohio, would say little about the president Monday other than to note he still supports Trump for re-election.

The Republican said the facts are out there for people to judge Trump's call to foreign powers to investigate a political competitor. “Certainly wouldn’t have been how I approached it,” was all DeWine would say on that topic.

Evan Machan, spokesman for the Ohio Republican Party, declined to comment.

But Ohio Democratic Chairman David Pepper was not reluctant to talk.

“Rob Portman is finally speaking up after allowing Donald Trump’s smear against Joe Biden and his family to go on for weeks or longer," Pepper said. "Last week reporters exposed a letter that Portman and his fellow senators signed back in 2016. Today, Portman admits that the letter actually backed up Biden’s account ... The idea that he’s already made up his mind that Donald Trump’s conduct — shaking down foreign leaders to do his political bidding — does not rise to the level of impeachment is ludicrous."

Portman said he first heard about Trump wanting a probe of the Bidens when it broke in the news a few weeks ago.

drowland@dispatch.com

@darreldrowland