Former vice president Joe Biden speaks at a rally Tuesday in Henderson, Nev. (John Locher/AP)
Columnist

Former vice president Joe Biden has risen significantly in Democratic primary polls since he formally entered the race last month. While he is now clearly the front-runner, there are many reasons to think the race will tighten considerably by the end of the year.

Right now, Biden is about as close to a generic Democrat as you can get. He benefits from his long track record of supporting Democratic Party priorities and his eight years as President Barack Obama’s loyal deputy. Being out of office for about the past three years also means he has had the luxury to pick and choose his moments of public engagement, which allowed him to avoid many of the intraparty fights and controversies.

That’s going to change once he gets on a debate stage with his opponents. Progressives such as Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (Mass.) will presumably push him from the left, while others such as former representative Beto O’Rourke (Tex.) will likely make his age a subtle issue by proclaiming a need for new leadership. Biden will have to withstand that pressure, showing he is progressive and energetic enough to give his supporters confidence.

Biden’s demeanor will be as much under scrutiny as his ideas. He was remarkably unsteady during his first campaign rally, stumbling over his scripted words again and again. Debates are notoriously unscripted. They are also hard work, requiring candidates to stand for 90 minutes under hot television lights late at night. Thoughts that he might be too old will quickly resurface if he can’t finish two sentences on his feet without slurring or mispronouncing words.

Running a complacent campaign can also cost him. So far, he has focused little on what he wants to do and much on attacking President Trump. But all of his competitors oppose Trump; they are also offering alternative visions of what Democrats should be for as well as what they should be against. Biden will have to do more than express gauzy Democratic pablum. It remains to be seen what Biden’s American vision is.

Biden’s current lead is also artificially large because the progressive vote is divided. Polls taken since his announcement show his lead is largest among Democratic voters who say they are moderates and smallest among those who say they are very or strongly liberal. The most progressive wing of the party is splitting its votes among a number of candidates, but eventually that will change. When a front-runner of that wing emerges, Biden’s lead will shrink considerably, even if he weathers his other challenges.

National polls this far out are not a reliable indicator of a candidate’s final strength. In April 2003, for example, former vice presidential nominee Joseph I. Lieberman led eventual nominee Sen. John F. Kerry (D-Mass.) in the Gallup poll. The men who would emerge as Kerry’s most serious challengers, Gov. Howard Dean (D-Vt.) and Sen. John Edwards (D-N.C.) polled in only the single digits. Even polls taken much closer to the first primaries can change dramatically. A December 2003 CBS poll,√ for example, showed Kerry receiving only 4 percent support while Dean was first with 23 percent. The next month, Kerry won the Iowa caucuses and Dean’s campaign was in a tailspin.

Biden starts in a strong position, but the race has only begun. With his age, his ideology and the divided progressive field, there are many reason to think his position could weaken, perhaps dramatically, as the campaign begins in earnest.

Read more:

David Byler: Black voters helped make Joe Biden the Democratic front-runner. Will they keep him there?

Ed Rogers: Why are some people down on Joe Biden?

Max Boot: Joe Biden is wrong about the GOP — but in the right way

Jennifer Rubin: How Joe Biden gets under Trump’s skin

David Ignatius: Joe Biden is the best candidate to beat Trump