In that 2012 race, Republican voters appeared at times quite willing to go with a different option than Romney. From late August 2011 through February 2012, Romney was surpassed no less than five different times in the national RealClearPolitics polling average, first by Perry, then Herman Cain, then Newt Gingrich (for two different stretches), and then, finally, Rick Santorum. Yet Romney always ended up back in the lead after his setbacks and emerged by the end of the first month of primary contests as the clear favorite to win the nomination (that year’s race started in January, not February). Romney benefited from split opposition as the primary season went along, with Santorum, Gingrich, and Ron Paul all cannibalizing the non-Romney vote.

Biden, meanwhile, has consistently led national polling. For a brief time in early October, Elizabeth Warren effectively tied Biden in the RealClearPolitics average, but Biden has since regained a decent-sized lead — he’s in the high 20s, with no one else within 10 points of his lead: Sens. Bernie Sanders (I-VT) and Elizabeth Warren (D-MA) along with South Bend Mayor Pete Buttigieg are all clustered within the low-to-mid teens.

Romney did always have a firewall in one of the lead-off contests: New Hampshire, where he enjoyed something of a home state advantage owing to his time as Massachusetts governor. That’s an advantage Biden does not have. In the first two contests, Biden trails in Iowa and New Hampshire. However, he leads in Nevada and South Carolina, which round out the February contests before March 3’s Super Tuesday kicks off a three-week barrage of primaries.