Early voting for the Texas primary starts Monday across the state. In Harris County, there are 37 early voting locations.
Voters can now pick their party's nominees after a four-month delay caused by an extended legal fight over the redrawing of political districts. But the delay could spell trouble for some Republican candidates facing opposition from hard-core conservative activists and the race could be decided by only a few hundred thousand ballots out of 13.5 million registered voters.
The first problem is just getting word out about the election. Texans are accustomed to voting on Super Tuesday, which this year was on March 6. The early date is designed to give Texans an early role in choosing presidential nominees.
But because of the lawsuit, Texans are voting after both President Barack Obama and Mitt Romney have basically clinched their party's nominations, which leads to the second problem. Without a big national race in the balance, primary voters tend not to show up. This year the biggest undecided race is to replace retiring U.S. Senator Kay Bailey Hutchison.
The third challenge is the May 29 primary date, which is the Tuesday after Memorial Day and as school closes for the summer. This is a popular week for people to take vacation. And that leads us to the importance of early voting.
Prudent experts and observers say they can't predict turn-out this year because there has never been a primary quite like this one.
"Anyone who claims they know what this weird, late May 29 primary is going to do for voter turnout is making stuff up," said Michael Quinn Sullivan, a conservative political activist. "I don't recall ever, in the history of Texas, having to move our primary at the last minute."
But Sullivan acknowledged that confusion often leads to low turnout, and with all of the legal wrangling around redistricting, this has been a confusing year.
There is also no doubt that voter enthusiasm makes a huge difference. When Obama and Hillary Clinton were neck-and-neck in the 2008 primary, more than 2.8 million Democrats voted, compared to 1.3 million Republicans. And yet, that still represented only 33 percent of registered voters, according to data from the Texas Secretary of State's office.
In comparison, the 2010 primary did not include a presidential race, and the biggest contest was Hutchison's challenge to Gov. Rick Perry. In that race, 1.48 million Republicans cast ballots, compared to only 680,000 Democrats.
This year Democratic turnout will likely run low again. Obama faces no serious challenger and the Senate nomination pits former state Rep. Paul Sadler against 32-year-old party activist Sean Hubbard. Donations are an indicator of voter enthusiasm and so far Sadler reports raising $77,800 and Hubbard $16,971.
The top three Republican candidates, by comparison, have raised between $5 million and $7 million. They will now spend much of that to encourage supporters to vote, since in recent elections early voters made up more than 40 percent of turnout.
For front-runner Lt. Gov. David Dewhurst, the goal is to win the May 29 primary with more than 50 percent of the vote, any less and he will face a July 31 runoff. Former Dallas Mayor Tom Leppert and former Texas Solicitor General Ted Cruz are each spending millions on television ads hoping to force that runoff, and if they succeed, they could have a chance to win.
That's because regular voters rarely take part in run-offs. In the Democratic Senate runoff off in 2006, voter turnout dropped from 509,370 voters in the primary to only 207,450 in the run-off. Barbara Ann Radnofsky won that race with 124,052 votes.
If Republican turnout this year is equal to the 2010 primary, then a candidate will need 740,001 votes to win. Less than that, and they will face a runoff where voter turnout will drop by at about half. That means the winning candidate will only need 370,001 to become the Republican nominee, and in Texas, that's almost a guaranteed trip to Washington for the next six years.
The Cruz campaign, in particular, is gambling on this strategy by focusing on mobilizing tea party supporters who are considered committed voters. In Indiana last week, a tea party candidate successfully defeated 36-year-veteran U.S. Sen. Richard Lugar in a primary where overall turnout was low, but tea party turnout was high.
All of the candidates know they need to get out their voters, so Texans will be getting a lot of phone calls from political campaigns beginning Monday urging them to vote. Because turnout, as always, will make the difference in who wins.