Heading into the homestretch of the Republican race, Mitt Romney is finally starting to open up a real lead over the rest of the field. But will it be enough to avoid a messy brokered convention in August? Following his big win Tuesday night in Illinois, Romney has secured 563 delegates, by the AP’s count. That’s a lot more than his nearest competitor, but to say he’s won the race is premature: It takes 1,144 delegates to sew up the GOP nomination, so technically he’s only halfway there.*

As the emphasis shifts from poll numbers to delegate math, here’s a look at how the candidates have fared so far and how far they are from the finish line. (You can also check Slate’s animation of the full GOP horse race based on polling data.)

In the above animation, each horse is a candidate, with its horizontal position representing that candidate’s delegate count. The numbers come from the Associated Press and include the stated preferences of some unpledged national party leaders. Check back regularly—we’ll update the race after each primary and caucus.

Correction, March 21, 2012: This article originally misstated the number of delegates required to earn the Republican presidential nomination. It is 1,144, not 1,114. (Return to the corrected sentence.)