Immigration could be Marco Rubio's Achilles Heel

Shhhh! Don't tell anyone, but Marco Rubio may be soft on illegal immigration.

While presenting himself as a rock-ribbed Republican conservative, the U.S. Senate candidate has a checkered past on border control.

An article posted on Politico.com today quotes Arturo Vargas, executive director for the National Association of Latino Elected and Appointed Officials, as saying Rubio, the son of Cuban exiles born in Miami, blocked scorched-earth legislation that sought to clamp down on illegal immigration.

He, as speaker, kept many of those from coming up to a vote, Vargas said. We were very proud of his work as speaker of the House.

In 2006, Rubio even voted for a bill that would have allowed the children of illegal immigrants to pay the same tuition rates at Florida colleges as residents.

Charlie Crist's camp is circulating this piece in an ongoing effort to undermine Rubio's conservative bona-fides, but it's far from clear that Crist would vote any differently.