Varying Treatment of Biden and Trump Puts Their Parties in Stark Relief

One of America’s political parties has a presidential candidate who is really old and showing it. The other has a presidential candidate who is a convicted felon, adjudicated sexual abuser, business fraudster and self-described aspiring dictator for a day. And also really old.

One of the parties is up in arms about its nominee and trying to figure out how to replace him at the last minute. The other is not.

The spectacle of the week since the nationally televised debate between President Biden and former President Donald J. Trump has thrown into sharp relief two political parties that agreed to be led by flawed putative nominees whose vulnerabilities have become even more painfully apparent just months before the election.

But the distinction of recent weeks has been striking. After Mr. Trump was found guilty of 34 felonies by a Manhattan jury in May — a verdict that came after civil judgments against him for personal and professional misdeeds — there was no significant groundswell within the Republican Party to force him out of the race in favor of a less-tainted candidate. Even though many Republican officeholders and strategists privately loathe him, they fell in line and made clear they would stick with him no matter how many scandals piled up.