As things stand now, it’s unclear whether the Ukraine “whistle blower” matter is a serious scandal. In my view, it will become one only if President Trump used American aid as a quid-pro-quo in trying to induce Ukraine to investigate the Bidens or if he significantly delayed the release of such aid because Ukraine hadn’t agreed to investigate.

For purposes of discussion, let’s assume this becomes a serious scandal, or at least one that the Democrats and the media firmly believe they can get major mileage from. Who would be hurt more, Donald Trump or Joe Biden?

I think Biden would be. In any plausible scenario I can foresee now, the Ukraine matter will not result in Trump’s removal from office via impeachment. Nor will it cost him the Republican nomination next year.

But a major Ukraine scandal could easily cost Biden the nomination. Why? Because Democrats cannot effectively make a big issue out of such a scandal as long as Biden is their nominee.

As I noted here, if Trump did make aid to Ukraine a quid-pro-quo for investigating the Bidens, this would be the mirror image of a pre-existing scandal involving Joe Biden. Biden has boasted that, by threatening to cut off $1 billion in loan guarantees to Ukraine, he caused the Ukrainian government to fire a prosecutor who was investigating a company that employed his son Hunter as a board member.

Biden will claim, in fact has claimed, that his desire to oust the Ukrainian prosecutor had nothing to do with the fact that the guy was investigating his son. He just thought the fellow was a bad prosecutor.

This argument doesn’t pass the straight face test. Democrats will not want to be saddled with it.

If party bosses still controlled the nomination process, and if they concluded that the Ukraine matter should be a major line of attack against Trump, they would kill the Biden nomination is a smoke-filled room.

Party bosses no longer control the nomination process (except when they do; see Clinton, Hillary). Primary voters and caucus goers do. But the polls suggest that the biggest thing in Biden’s favor is his supposed strength as a candidate against Trump. Moreover, Democratic voters, frustrated by the demise of the Russia collusion theory, are dying to find another scandal like it with which to pummel the president.

If the Ukraine matter looms large heading into next year, voters might well conclude that Biden’s supposed electoral advantage is overrated or non-existent, and might well favor a candidate who isn’t tied to things Ukrainian.

One such candidate, Elizabeth Warren, may already be ahead of Biden in Iowa and New Hampshire. Depending on how it breaks, the Ukraine matter might boost her above Biden in national polls before long.