For weeks, Mr. McAuliffe has made little mention of President Biden, instead using his campaign rallies, media interviews and millions of dollars in campaign advertising to make the race all about former President Donald J. Trump.

In a way, Mr. Biden’s scheduled campaign stop with Mr. McAuliffe Tuesday evening, as part of a last-week effort to energize Democratic voters, highlights just how little he has been present in the race at all.

The delicate distance Mr. McAuliffe has put between his campaign and the president, his friend of four decades — whom Mr. McAuliffe helped carry Virginia by 10 points just a year ago — underscores a difficult reality for Democrats looking anxiously ahead to the midterm elections next year. With his moderate, art-of-the-possible politics, Mr. Biden fails to rouse anywhere near the same passions as Mr. Trump, who spurred Democrats to the polls in record numbers throughout his four years in office. Nor has Mr. Biden’s administration given Mr. McAuliffe much to advertise, after months of Democratic infighting on Capitol Hill over the president’s dwindling domestic ambitions.