Texans know the lesson well.

On primary election night, it’s not always about the popular vote. It’s also about the delegates.

That sentiment has lingered since Democratic presidential candidate Hillary Clinton won the popular vote here in 2008 but saw more delegates go to her opponent, Barack Obama, under a now-obsolete two-tiered system.

“The ‘two-step’ in ’08 made Barack Obama and gave him the opportunity to claim the presidential nomination,” said Jim Riddlesperger, a political science professor at TCU. “Texas is a huge state and the delegates here of course can make a difference in someone’s campaign.

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“Texas is by far the most important state on Super Tuesday,” he said. “If you’re thinking someone can stop Donald Trump for the Republican Party nomination — and a number of Republicans would like to see him lose — the firewall may be gone by the time Super Tuesday ends.”

Record early voting turnout in Tarrant County may mean that a larger than average number of local voters will head to precinct conventions after the polls close Tuesday, hoping to serve as a delegate for their presidential pick.

Statewide, early voting came close to the 2008 turnout, but didn’t match the large numbers: 1.1 million Texans voted early this primary, compared with 1.9 million Texans in 2008.

But Tarrant County voters broke the historic turnout from eight years ago here, with 139,396 voters — 95,088 Republicans and 44,308 Democrats — heading to the polls early this year. In 2008, 123,343 local voters —36,759 Republicans and 86,584 Democrats — casting early votes, according to state election records.

To claim the overall presidential nomination, a Republican needs 1,237 delegates and a Democrat needs 2,383 delegates.

Texas voters head to the polls Tuesday, March 1.

Texas offers candidates a treasure trove of delegates: 155 Republicans and 251 Democrats.

It’s highly unlikely that one candidate will claim all the delegates, unless one of them claims victory by a landslide.

But a win in Texas could put a candidate much closer to his or her overall goal.

“No one will leave Texas with a majority of the delegates,” said Brandon Rottinghaus, an associate professor of political science at the University of Houston. “Like 2008, the popular votes and delegates are decoupled, allowing one candidate to win the statewide vote but another to win in more districts, netting more delegates.

“This underscores the need for campaigns to focus on areas where they are strong and their opponents less strong,” he said. “A campaign's best bet is to fish where the fishing is good. “

Here’s a look at how both parties will award their delegates.

Republicans

Republicans have a somewhat complicated way of awarding delegates. Here’s a look at how it’s done, according to a report by Eric Opiela, assistant general counsel to the state Republican Party.

155 Number of Republican delegates Texas has to offer

Delegates are awarded to presidential candidates based on results of votes in each of the state’s 36 congressional districts. Three delegates per district, for a total of 108 delegates, will be determined this way.

If a candidate receives more than 50 percent in a congressional district, he or she claims all three delegates. If one candidate receives 20 percent or more, the candidate with the most votes receives two delegates and the No. 2 vote-getter receives one. If no candidate receives 20 percent in a congressional district, then the top three vote-getters get one delegate each.

“Given the rules, Republican candidates want to campaign in places where they can get more than 50 percent of the votes, giving them all the delegates in an area,” Rottinghaus said. “Short of that, they want to keep their opponents’ vote percentage lower so they can get more delegates.

“The strategy is part offense and part defense.”

And 47 at-large delegates will be allocated based on statewide election results. If a candidate receives a majority of the statewide vote, all those delegates are allocated to that candidate. If not, and more than one candidate receives at least 20 percent of the vote, only the candidates receiving more than 20 percent may claim delegates.

If any candidate withdraws from the race, the delegates that would have gone to him or her become “uncommitted” or “lapsed” delegates and are awarded to a candidate still in the race.

Democrats

In the past, Texas Democrats awarded their delegates through a two-tiered system called the “Texas Two-Step,” which awards delegates to candidates through both a popular vote on election night and also through postelection caucuses.

251 Number of Democratic delegates Texas has to offer

But last year, the state Democratic Party scrapped the system, shifting to a more traditional way of parceling out delegates based solely on the primary results.

Now, an extremely popular Democratic candidate could claim all the delegates if he or she wins 85 percent of the statewide vote.

Otherwise, delegates are awarded to candidates based on a formula.

There are 145 Senate district delegates. A presidential candidate must receive 15 percent or more of the vote in a district to receive any delegates.

“With Hillary Clinton ahead statewide and in many regions, her strategic play is to keep Sanders’ vote share lower in districts where he might not get to 15 percent and she can capture all the delegates,” Rottinghaus said.

There are 48 pledged at-large delegates, 29 pledged party and elected official delegates and 29 unpledged delegates.

And there are 19 at-large alternates.