Lt. Gov. David Dewhurst is very likely to be the clear first-place finisher in tonight’s GOP Senate primary in Texas.

U.S. Senate candidate Ted Cruz greets supporters at The Tea Party Express rally at the Capitol in Austin, Texas, on May 6. (AP Photo/Austin American-Statesman, Jay Janner)

In Texas, the race to replace retiring Sen. Kay Bailey Hutchison (R-Texas) is all about the GOP primary, after Democrats’ prized recruit — former general Ricardo Sanchez — crashed and burned early in the race.

The GOP contest so far has been a bit of a jumbled mess, and Dewhurst’s top tea party competition, former state solicitor general Ted Cruz, has been badly outspent in a crowded field that includes former Dallas mayor Tom Leppert.

Still, Cruz appears to be the top threat to gain a two-man runoff with Dewhurst, and even if he finishes far behind Dewhurst today, it’s hard to count him out in the July 31 runoff.

Here’s why:

1. Time

If there is a runoff, it will occur July 31 — a full nine weeks after today’s primary. Runoffs, which are held in many Southern states, are generally four- or six-week sprints after a primary in which the candidates have already spent down their resources and then have to ramp up in a hurry for a quick race.

That compressed calendar generally favors the candidate who finished first in the initial race. But adding another month can galvanize much more support for the second-place finisher. And it gives Cruz much more time to close what is a sizeable early gap (more on that later).

Also keep in mind: Cruz benefitted when the primary was pushed from March to May thanks to the ongoing uncertainty over the state’s redistricting maps. It gave him more time to build up name identification against the well-known and very well-funded Dewhurst.

2. Money

Cruz has raised and spent about one-quarter of what Dewhurst has and he’s also been outspent by Leppert. (Both men were able to self-fund millions for their bids.) And without the race crystallizing into a Dewhurst-vs.-Cruz battle, the tea party organization hasn’t completely mobilized behind Cruz’s candidacy. (After all, why waste resources without knowing there will be a runoff with your candidate in it?)

If the race goes to a nine-week runoff, that tea party organization should be able to help Cruz be much more competitive — if (and that’s still an “if”) groups like the Club for Growth want to spend big money in what is a very expensive state.

Keep in mind, though, that Dewhurst has millions of personal money at his disposal and he will be outspend Cruz and any aligned groups. The gap just might not be as big the second time around.

3. Low turnout

With the presidential primary and many competitive congressional primaries on the ballot today, turnout is expected to be relatively high (for a primary). If it goes to a runoff in the middle of the summer, it’s hard to see it being a high turnout affair.

Generally in Texas, turnout drops by more than half for a runoff. That means the race comes down to more motivated voters; and more motivated voters tend to be more conservative, which could favor a tea party candidate like Cruz.

Polling at this point shows Dewhurst starts a runoff as a clear favorite; a survey this weekend from Democratic-leaning automated pollster Public Policy Polling showed Dewhurst starting with a 59 percent to 34 percent lead in a head-to-head matchup with Cruz — largely thanks to Leppert voters going overwhelmingly for Dewhurst.

It’s clear that Dewhurst would be a formidable candidate even if he can’t win the nomination outright tonight. But given the particulars of the runoff, it’s hard to say that the race wouldn’t wind up being competitive if Cruz can marshal the kind of resources that have been available to tea party favorites in the past.