Jonah Goldberg explains at National Review Online how President Trump’s campaign against possible Democratic challenger Joe Biden could backfire.

Is President Trump going to get Joe Biden elected?

Opinions vary widely on how to characterize Trump’s now-infamous conversation with Ukrainian president Volodymyr Zelensky. The president believes it was “perfect” and “beautiful.” In the middle are those who think it was bad and improper or perhaps impeachable but not necessarily worth the bother this close to a national election. And then there are those who believe we know all we need to know to warrant impeachment and removal right now.

But one thing virtually every sentient being agrees on, even if some won’t say so publicly, is that if Biden weren’t running for president — and outpolling Trump in general-election matchups — Trump would be a lot less interested in Biden’s alleged misdeeds.

And that raises the amusing possibility that Trump’s effort to damage Biden might, just might, end up being a blessing in disguise for the former vice president.

The Trump-impeachment firestorm ignited just as Biden was declining a bit in the polls and Senator Elizabeth Warren of Massachusetts was starting to surge. …

… The Ukraine story is still unfolding, and there’s too much churn and uncertainty to gauge or predict its effects. Moreover, the speculation that Biden simply isn’t up to the challenge the way he once was is hardly baseless. That said, the all-out assault on Biden just might go down in history as one of the great examples of unintended consequences in American politics.