AUSTIN, Texas -- For the first time in 20 years, Texas will have a heated presidential primary election next month.

The contest that will bring the state's complex primary and caucus system into play for Democratic hopefuls Hillary Rodham Clinton and Barack Obama.

Corpus Christi state Representative Juan Garcia's an Obama supporter. He tells the Houston Chronicle that "Texas arguably has the most arcane system in the country." He says "there are a lot of people scrambling to get smart on it in a hurry."

The Clinton-Obama tussle for national convention delegates is extremely tight, especially after Obama's victories Saturday in Nebraska, Washington and Louisiana. The Democratic and Republican primaries in Texas are on March 4.

Here's a short version of the Texas Democratic Party rules for awarding national convention delegates:

Texas will award 126 Democratic convention delegates based on the outcome of the vote in each of the 31 state senatorial districts. But the number of delegates available in each district isn't equal. Delegates are allocated based on the votes cast in districts in the 2004 and 2006 presidential and gubernatorial elections.

In the heavily urban, black districts of state Senators Rodney Ellis of Houston and Royce West of Dallas, a good voter turnout in the past two elections means a combined total of 13 delegates are at stake in the two districts on Election Day.

Obama nationally has been winning 8 out of 10 black voters, according to network exit polls.

But in the heavily Hispanic districts of state Senators Juan Hinojosa of McAllen and Eddie Lucio Jr. of Brownsville, election turnout was low and a combined total of seven delegates are at stake.

Clinton has been taking 6 of 10 Hispanic votes nationally, so a big South Texas win might not mean as much for Clinton as a big win for Obama in the two black districts.

The last time the Texas Democratic convention delegation was at stake in the midst of a national fight was 1988. Michael Dukakis won the statewide primary that year but virtually split delegates evenly with Jesse Jackson because of the state's unique Democratic nominating process.