Ted Cruz's victory in the Wisconsin primary was a turning point in the Republican presidential race in more ways than one.

It means Donald Trump is less likely than before to have locked up the GOP nomination when the last primaries are over on June 7. And preventing Trump from achieving that is Cruz's chief objective at this point.

It also means that Trump will be under enormous pressure to improve his personal campaign style. He claims he can adopt a more "presidential" posture whenever he wants to. After his embarrassing effort in Wisconsin, Trump may decide now is the time.

But there's another part of the race that now comes into play: the weeks between the end of the primaries and the start of the GOP convention in Cleveland on July 18. That is when the nomination may be decided rather than at the convention itself.

How so? There will be 150 or so uncommitted delegates, plus delegates pledged to candidates no longer in the race. The major figures here are John Kasich, assuming he has conceded his chance of being the nominee are non-existent, and Marco Rubio, who has dropped out.

Both Trump and Cruz will try to attract as many of those delegates as possible. And Trump ought be in a stronger position because he's likely to need only a few dozen additional delegates to reach a majority of 1,237 and win on the first ballot.

If Trump is as good a negotiator as he insists he is, that would give him another advantage. No telling what he might offer individual delegates or what he might dangle at Kasich or Rubio. But asking either Kasich or Rubio to be his vice presidential running mate is conceivable.

In Cruz's case, there's less to offer. There probably won't be enough unpledged or otherwise available delegates for him to reach the 1,237 mark.

But Cruz has two strengths Trump lacks. One is electability – that is, who has the better prospect of defeating Hillary Clinton in the general election. Polls show Cruz does. Kasich does better than either Cruz or Trump, but his notion of being nominated at a "magical" convention is fanciful.

Up to now, Republican voters haven't taken electability seriously. They've voted for the candidate they like, not the one with the best chance of being elected president. The exit poll in Wisconsin found that only 11 percent of Republican voters regard electability as the "top candidate quality."

But that will change once the primaries end and the general election starts to come to focus. Are uncommitted delegates likely to back a candidate like Trump who looks like a loser to Clinton in November? I don't think so.

The other consideration is party unity. Which candidate can bring about the most unity among Republicans? Or put another way, which one can keep the party from splitting? Cruz, linked to the party's dominant conservative wing, has the upper hand here.