The battle between Donald Trump and Ted Cruz has finally begun. A few thoughts on this long-anticipated fight:
(1) The timing is noteworthy. Whereas other candidates—above all Jeb Bush—have been trying, with limited success, to hit Trump for some time, Cruz has held back. Here's why: The decision-making process of primary and caucus voters must dictate the timing; they are only now beginning to engage, so now is the time that attacks can really influence the outcome.
Consider, for instance, the late movements in Iowa in 2012, when Rick Santorum came out of nowhere to defeat Mitt Romney narrowly. Consider also 2008. Even though Mike Huckabee had already broken away by this point, there was still notable movement. John McCain was just around 5 points with two weeks to go, but finished with more than 13 points. That might not seem like a lot, but an 8-10 point swing in Iowa in 2016 could be enormously important. On the Democratic side, Hillary Clinton still had a small lead around this time in the 2008 cycle in Iowa, and John Kerry was still quite far from first place at this point in 2004.
So, it makes sense for this fight to happen late, because primary voters make their decisions late.
(2) It was probably inevitable. Ideally, Cruz would have preferred not to attack Trump, under the hope that somehow the latter would fade away. But it has been apparent for some time that this was not going to happen.