Former Vice President Joe Biden speaks with Senator Elizabeth Warren during the 2020 Democratic U.S. presidential debate in Houston, Texas, September 12, 2019.Mike Blake | ReutersPresident Trump’s Ukraine phone call controversy has all the makings of another scandal likely to fail to do any permanent damage. But for two of his Democratic presidential rivals, this is a matter of political life or death. This scenario feels like just another spoke in a wheel that’s been turning since October 2016 and the release of the “Access Hollywood” tape. That recording, filled with Trump making repeated vulgar claims about his interactions with women, would likely have been fatal to just about any politician’s presidential aspirations.But Trump because he is a street fighter who naturally takes to the nasty insults associated with politics and simply never tried to project a squeaky clean image in the first place.That’s the same reason why the Russian collusion narrative never fatally damaged him. Trying to make second-hand contacts with Russians claiming to have dirt on Hillary Clinton that never panned out certainly didn’t look good, but it was nothing close to any grand conspiracy or enough to even lead to a definitive conclusion in special counsel Robert Mueller’s report.Democrats and the president’s other opponents should have learned that simply embarrassing Trump doesn’t work. While even some Republicans in Congress are expressing concerns over what they’ve seen in the Ukraine call’s transcript, remember that even more Republicans completely disavowed then-candidate Trump after the “Access Hollywood” tape release. On a 1-10 scale of damaging embarrassing moments for President Trump, with 10 being an “Access Hollywood” level embarrassment and 1 being one of his many nasty tweets about a celebrity, this Ukraine phone call rates at about a 5 or 6.That’s not enough to run with an impeachment inquiry when the Constitution requires impeachment charges to encompass high crimes or misdemeanors. Luckily for the Democrats, committees in the House are only in the “impeachment inquiry” stage and they can drag this out as long as they want before having to do the riskier and tougher job of voting on an actual article of impeachment.But there is a much bigger loser in this incident. It’s clearly Democratic presidential frontrunner Joe Biden. His quest for the nomination has likely been dealt a fatal blow. That’s because unlike Trump, Biden is a career politician who simply can’t afford to lose any moral high ground if he hopes to make a strong alternative case for himself against Trump in 2020. Even Biden’s campaign knows the extreme value that moral high ground is to his entire brand, as it pushes the narrative that the real reason he entered the race was to take the moral high ground over Trump in response to the president’s reaction to the 2017 racist marches in Charlottesville.Now the news and social media are filled with questions about how Biden’s son Hunter was even remotely qualified to receive hefty payments from Ukrainian companies. Perhaps there is an innocent explanation for it, but so far both Joe and Hunter Biden haven’t provided any. Instead, candidate Biden has failed to react in the best way by choosing a public statement Tuesday where simply bashed President Trump and took no questions from the assembled news media.Just as Democrats in Congress are seeking to remove President Trump over allegations of improper dealings with the Ukrainian government, how in the world can the same party nominate a man accused of essentially doing the same thing?So who’s the potential winner in all of this?That would be Sen. Elizabeth Warren, who has been making major gains on Biden in the polls and even leads Biden in some new surveys.But so far, Warren is showing signs she may fumble this opportunity. Warren was unable to give a definitive answer to a reporter Wednesday on whether she would allow something like it in her administration. If ever there was a time to take a page from President Trump’s 2016 campaign book and slam her main primary opponent, this is it.Coupled with her continuing inability to provide a definitive answer about middle income tax hikes to pay for her “Medicare for All” plan, this is the second time in a month that Warren is shrinking from her usual habit of making clear and strong statements about every issue. Warren has been touting her new plan to stamp out corruption in politics, but she hasn’t taken the opportunity to clarify and strengthen her stance on the Biden connection to Ukraine. She still has time, but not much.Either Warren needs a new campaign manager or she needs to ask herself if she’s hungry enough for the job in the first place.