After a decisive victory in the Illinois Republican presidential primary, former Massachusetts governor Mitt Romney is breathing a little easier than he was a week ago.  Having outspent his nearest rival, former Senator Rick Santorum 7 to 1 in Illinois, he will win most of the state’s delegates.  More importantly, he gains momentum for his candidacy.

In his speech on Tuesday night, a triumphant Romney didn’t talk about the inevitability of winning the nomination, but acted like an inevitable nominee.   "Elections are about choices. And today hundreds of thousands of Illinois voters have joined millions across the country in our cause," he said.  Romney spoke with enthusiasm, and if he's to be a serious contender in November, he will need to his supporters to be more enthusiastic about his candidacy than they have been thus far.

With more than half of the states and territories already weighing in, in state after state, results have shown both Romney and Santorum win their base of support but don’t expand into the other’s camp or bring in new voters. While the math makes it nearly impossible for Santorum to win the nomination, he's vowed to take his fight to the Republican Convention in Tampa, Florida in August. There, he hopes to convince delegates to switch their allegiance.  Republicans haven’t chosen their nominee that way since 1948.   

While the delegate math isn’t in his favour, Santorum is raising more money than ever, meaning he’s not leaving this race anytime soon. In February, he took in $8.9m. Romney also did well, hauling in $11.3m, meaning he can continue spending big to woo voters.

The longer this fight goes on, the shorter amount of time the eventual nominee has to mount an offensive against Barack Obama.  But while some say a protracted primary battle will hurt the eventual nominee’s chances, that argument didn’t apply to the long campaign waged between Barack Obama and Hillary Clinton.    

The difference between 2008 and 2012 is the force of enthusiasm. In 2008, Democrats got energized watching the candidates reshape their messages which built momentum for the November General Election. When the fight was over, the party was united and strong.   

This year, the Republican contenders haven't honed their policy positions or energised new voters.  And so the remaining Republican candidates move on to the next primary, which takes place on Saturday in Louisiana, short on enthusiasm and momentum.