Maggie Haberman at Politico wrote this week about Hillary Clinton's capacity to freeze the Democratic presidential field. It's hard to see anyone else getting traction as long as Clinton looks set to run. And if she opts out late in the process, or falters in health or otherwise during the campaign, Democrats will be in very bad shape indeed.

Still, she's never given any indication that she needs much persuasion to run. And despite Democrats' perpetual infatuation with shiny new liberals, the party will be much more protective of her claim to the highest office in 2016 than it was 2008.

Why?

Women. Binders upon binders full of 'em. The Barack Obama presidency -- with a major assist from Republicans -- has cemented Democrats' hold on black voters while strengthening the party's ties to Hispanics and Asians. Along with college-educated white liberals, this makes for a sizable electoral base. But for years Democrats have been trying to add another key piece to the foundation: non-college-educated white women. More than a few Democrats suspect that a Clinton 2016 campaign might end the years of frustration.

Let's pick a not-entirely-random state: Ohio. In 2008, Clinton beat Obama among white women in the Democratic primary by more than 2-to-1. Clinton won high-school graduates by 2-to-1 while the two candidates split college grads. And even in the Democratic primary, one in five voters said the race of the candidate was important to them. Were these blacks excitedly casting an historic ballot for the first viable black candidate for president? Actually, most of the voters who said race mattered to them voted for Clinton.

Obama never came close to sealing the deal with non-college white women. Nationally in 2012, Mitt Romney defeated Obama among white women overall by 56-to-42.

Maybe 2016 will be another non-college bust for Democrats. But if they're salivating at the prospect of a Clinton campaign, it's partly because they believe she has the potential to hold the gains Obama has made with minorities while adding the last piece of the puzzle: non-college women. If that conjecture is right, the only way Republicans will get inside the White House is with a visitor's pass.

(Francis Wilkinson is a member of the Bloomberg View editorial board. Follow him on Twitter.)