( CNN ) -- It 's all tied up in Texas . Sens . Hillary Clinton and Barack Obama are running a tight race in Texas . A new CNN/Opinion Research Corp. poll suggests the battle for the Democratic presidential nomination between Sens . Hillary Clinton of New York and Barack Obama of Illinois is a statistical dead heat in Texas , which holds primaries March 4 . In the survey , out Monday , 50 percent of likely Democratic primary voters support Clinton as their choice for the party 's nominee , with 48 percent backing Obama . But taking into account the poll 's sampling error of plus or minus 4½ percentage points for Democratic respondents , the race is a virtual tie . Watch Democrats target Texas . » . Two recent polls by other organizations also show the race statistically even . Map : National and state polling . `` One reason the race appears to be tight is that Texas Democrats are having a hard time choosing between two attractive options , '' says CNN polling director Keating Holland . `` Likely Democratic primary voters would be equally happy if either candidate won the nomination , and they do n't see a lot of difference between them on several top issues . `` Roughly a quarter of likely voters say they could change their minds in the next two weeks -- and not surprisingly , those people are splitting roughly equally between Clinton and Obama . '' Many political strategists and analysts consider Texas and Ohio -- which also holds a March 4 primary -- must-win states for Clinton . Obama has won the past eight contests and is now ahead in the overall battle for delegates , 193 of which are at stake in Texas . The new survey indicates Arizona Sen. John McCain is the clear favorite for the Republican presidential nomination . Among Republicans , 55 percent of likely Texas GOP primary voters support McCain as their choice for nominee . Thirty-two percent back former Arkansas Gov . Mike Huckabee and 11 percent support home-state congressman and former Libertarian standard-bearer Ron Paul . The poll 's sampling error for Republican respondents is 4 percentage points . The CNN/Opinion Research Corp. poll was conducted by telephone from Friday through Sunday . Pollsters talked to 1,506 adults in Texas , including 553 likely Republican primary voters and 529 likely Democratic primary voters . McCain is the overwhelming front-runner in the fight for the Republican presidential nomination and party leaders have rallied around the candidate in an attempt for party unity . The poll was released on the same day the only living former Republican president -- George Herbert Walker Bush , the current president 's father -- endorsed McCain at an event in Houston . Watch McCain get a big boost » . But McCain has had trouble winning conservative voters . Just last week , McCain lost the conservative vote to Huckabee in the Virginia primary , according to exit polls . The new survey , though , suggests McCain may have better luck in Texas . `` It looks like McCain has made some inroads with conservative Republicans , '' Holland said . `` McCain is picking up a bare majority among conservative likely voters in the GOP primary . The McCain campaign probably wishes that number were higher , but it does mean that a McCain victory in Texas would not be based on the votes of moderates and independents , as has happened in several states in the past few weeks . '' Texas Democrats and Republicans may not see eye to eye on the issues , but the poll suggests they do agree on what 's the most important issue . Thirty-five percent of Democrats and an equal number of Republicans said the economy was the most important issue in their choice for president . The second most important issue for Democrats was health care , at 23 percent , followed by the war in Iraq at 22 percent , illegal immigration at 10 percent and terrorism at 7 percent . Nineteen percent of Republicans said illegal immigration was their most important issue , putting it in second place , followed by the war in Iraq and terrorism at 17 percent and health care at 8 percent . Sixty percent of Republicans say they 'll definitely support the candidate they are now backing . That number climbs to 76 percent for Democrats . Likely Democratic primary voters view Clinton and Obama on roughly equal terms . Seventy-nine percent say they would be satisfied if Clinton were the nominee ; an equal number feel the same way about Obama . Seventy-nine percent say it 's likely Clinton can win the nomination ; 82 percent say the same about Obama . The two candidates are essentially tied on immigration , Iraq and the economy , but Clinton has an advantage on health care and abortion . E-mail to a friend .
Texas voters go to the polls March 4 . Sen. John McCain is the clear front-runner on the Republican side . Sen. Barack Obama is on an eight-state winning streak . Some strategists see Texas as a must-win state for Sen. Hillary Clinton .