A caravan of union members mostly from Los Angeles led a crowd of about 1,500 people into Bakersfield, California on Wednesday, where they braved 100-degree temperatures in rallying for immigration reform legislation with a path to citizenship for the undocumented. Bakersfield is the congressional district of House Majority Whip Kevin McCarthy (R-Calif.), the third-ranking Republican in the House who has turned into the biggest target for immigration activists on the left this August. McCarthy's district is 35 percent Latino, and immigrant advocates are both reminding him every chance they get and trying to make sure that constituency knows about where McCarthy stands about extending rights to undocumented immigrants.

"Kevin, if you don't support immigration reform your party will be extinct," read one sign. The Associated Press described the sign as being perched on a truck next to a large stuffed dinosaur bearing a photo of McCarthy's face.

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In a statement, McCarthy appeared to be standing firm. "I have long said that our immigration system is broken, but rather than take up the Senate bill, the House will move in a step by step approach that first secures the border," he said.

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Supporters of a comprehensive immigration reform bill with a path to citizenship for the undocumented have been using the five-week congressional recess to pressure House Republicans with sizable Hispanic contingents in their constituency. McCarthy's Bakersfield district in particular has been a focal point: earlier this month, his offices were the target of a sit-in by activists. After that, according to Politico, McCarthy agreed to meet privately last week with the Service Employees International Union, the Coalition for Humane Immigrants Rights of Los Angeles and Barack Obama's campaign group Organizing for Action.

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Bakersfield will see another big group of ralliers from out of town later this August, when activists from Sacramento come to McCarthy's district to urge him to consider a comprehensive reform.

In an interview with Politico, Arturo Rodriguez, the president of the United Farm Workers, said of McCarthy, "He has a large number of Latinos in his district, he also has agriculture as the No. 1 industry here. If he's listening to his constituents, they support it. He can't ignore that."