None of us know how the Ukraine saga will end, but one thing seems clear already: Donald Trump is not the only one at risk. This is going to hurt Joe Biden, too, and could scramble the Democratic race.

It’s almost obscene to compare Biden’s sins to Trump’s. Biden is a decent man, not a criminal.

But he screwed up big-time by allowing his son, Hunter, to make a killing in the Ukraine trading on daddy’s name. Hunter took a fat job in an industry he knew nothing about, two months after being thrown out of the U.S. Navy Reserve for cocaine use. He made up to $50,000 a month while his dad was point-man on Ukraine policy for the Obama administration, and while he bounced in and out of rehab for drugs and alcohol.

It’s not a crime, like Trump asking Ukraine and China to meddle in the 2020 election. But it’s the kind of obnoxious behavior by Washington elites that voters resent.

And Biden’s attempt to shoo this away as fake news is not going to fly. This part of the attack on him is true.

“This was a horrible error in judgment by Hunter Biden, and Joe should have used whatever influence he had with his son to ask him not to be involved,” says Julie Roginsky, a Democratic consultant who has managed several statewide campaigns.

“I understand his reluctance to engage because it perpetuates the story, but I think that’s a miscalculation. Voters want someone who will take it to Trump every day. I’m disappointed Biden hasn’t been doing that as effectively as he should be, and I love Joe Biden, I’m a massive fan.”

I’m not a massive fan, but I want the strongest fighter in the ring against the Mad King, and polls show Biden crushing Trump by double digits in swing states like Pennsylvania, Michigan, and Wisconsin.

That’s made me a Biden man until now. So, when he rambles in the debates, it pains me. When his critics note that he was a cheerleader for the biggest mistake of our era in foreign affairs (the Iraq invasion) and in domestic affairs (the drug war), I close my eyes and think about those polls in Pennsylvania.

But now I worry. Maybe Biden isn’t the safe bet after all.

Patrick Murray, director of the Monmouth poll, tells me to simmer down, and adds some useful nuance.

Among Democrats, he says, 21 percent believe that Biden “probably” did pressure Ukraine to end a corruption investigation into the natural gas company where his son sat on the board, Burisma Holdings.

Keep in mind, that charge is pure Fox News nonsense, like Obama’s birth in Kenya. Biden was the good guy in Ukraine’s corruption fight. He pressured Ukraine to replace a complicit prosecutor whose dismissal was sought by European governments, the U.S. State Department, the International Monetary Fund, and Ukrainian reformers.

Biden was advancing a widely known American policy, not freelancing on behalf of his son. That charge is a flat-out lie, without a spec of evidence to support it.

But this is America, where facts are out of style, so let’s turn back to the politics.

Murray found those 21 percent of Democrats who believe this slander were not Biden supporters to begin with, suggesting their defection won’t hurt him much in the primaries. In fact, Murray sees an opportunity for Biden to gain ground by punching back, just as Roginsky suggests.

“What Democrats are looking for is a fighter,” Murray says. “Biden doesn’t have to defend his behavior. What they’re looking at is, ‘You told us you could take on Donald Trump. Now he’s throwing a punch. Can you throw one back?’”

Sen. Elizabeth Warren can punch and was gaining ground before anyone knew Hunter Biden’s name. She’s now beating Biden in early state polls, and she’s raising money faster than he can as well.

Earlier this month, Warren released a plan to fight corruption, a top issue for voters, mainly by attacking conflicts of interest among Washington elites. Biden can’t make that pitch now, and that takes away a big weapon against Trump.

Warren, of course, will have competition in the fight for any Biden voters who peel off, starting with Sen. Bernie Sanders, Sen. Kamala Harris and Mayor Pete Buttigieg, the next three in the polls.

I wonder if it could shake Sen. Cory Booker out of the basement. He was at 1 percent in Murray’s latest poll.

“Booker’s low standing has been one of the most surprising aspects of this race,” Murray says. “He makes an emotional connection, and they love him when they see him. But I think they wake up the next morning and say to themselves, ‘He’s more of a cheerleader than a quarterback.’”

Roginsky wonders if that might change, assuming that Biden voters start jumping ship. “It’s a huge opening for Booker,” she says.

If Biden’s campaign trips over his son, it would seem wildly unfair, given that Trump has flagrantly abused his office to enrich himself and his three grown children. When he says Biden is corrupt, he gives new meaning to the word chutzpah.

But this is a moment for Democrats to be cold-hearted, to put aside any affection for Biden and make a hard calculation about his odds of winning. If he emerges wounded by this, which seems likely to me, then they need to find a stronger horse.

More: Tom Moran columns

Tom Moran may be reached at tmoran@starledger.com or call (973) 836-4909. Follow him on Twitter @tomamoran. Find NJ.com Opinion on Facebook.