PHOENIX — Late on the afternoon of Super Tuesday, one of Arizona’s most entrenched and prominent Latino politicians strode into the Greater Phoenix Progressive Christian Church and voted for Hillary Clinton. Few recognized Rep. Ed Pastor, who after voting raced to his car, pulled out a clipboard and stood in the parking lot seeking signatures on petitions to land him on the ballot this fall.

Pastor, who has served in Congress since 1991, has long taken the pulse of Arizona’s burgeoning Latino electorate, and earlier in the day had visited heavily Latino districts, where voter turnout was brisk and unprecedented, despite new laws requiring picture IDs.

“Latinos I believe will favor Hillary Clinton because she is familiar to them and they are comfortable with her,” Pastor told Salon.

Popular Gov. Janet Napolitano, on the other hand, has endorsed Barack Obama. The Latino community is sharply divided over immigration issues, and Napolitano drew criticism in 2007 when she signed into law a bill sanctioning employers who hire illegal immigrants.

Arizona’s 673,000 Latino voters, 17 percent of the electorate, will be critically important to the outcome of Tuesday’s Democratic primary, and their choice of candidates could be an indicator of how the Latino vote will break nationally. A January poll showed that Arizona Latinos favored Clinton by almost four to one over Barack Obama, but with nearly one in three voters undecided.

Arcelia Carrasco, a 52-year-old food-processing plant worker, was standing in line to vote for Clinton at the Greater Phoenix church at noon. She had started work at 4 a.m. and reported to the polling place after an eight-hour shift of chopping vegetables. Carrasco, now an American citizen, has been battling to get legal work status in America for her 30-year-old son, who was born in Mexico. She opposes the employer sanctions act, but that didn’t turn her against Obama. She voted for Clinton simply because she figured if anyone could help her, Clinton could, because Clinton is a mother too.

“I voted with my heart,” Carrasco said.