The race is on, and in a dead heat, as I described in my column this week. The focus for Mitt Romney is not only on shoring up support among conservatives who supported his rivals during the primary season, but on his pivot to a general-election electorate. Romney faces the greatest challenge appealing to female voters and Latinos, as polls currently show him far behind President Obama with both groups.

During the primary campaign, Romney used the issue of immigration to draw contrasts between himself and Texas Gov. Rick Perry, as well as with former House Speaker Newt Gingrich (Ga.). Romney not only pledged to veto the DREAM Act, but said Arizona's new, controversial immigration law was a "model" for the nation. He also characterized Perry's support of in-state tuition for children of illegal immigrants as "a magnet."

Sen. Marco RubioMarco Antonio RubioCongress faces growing health care crisis in Puerto Rico The Hill's 12:30 Report Colbert mocks Trump for sipping water during speech on Asia trip MORE (R-Fla.), one of the top contenders to be Romney's running mate, is preparing legislation that would bridge the gap between the GOP's hard line on immigration and the Democrats' failure to fulfill a promise of action on comprehensive immigration reform. He is reaching out to activists in the immigration community, trying to find an opening among those frustrated by Obama's failure to follow through on a campaign promise and address the contentious issue after more than three years in office.

White House officials are telling those same activists that Rubio can't get Republicans on board, that the legislation doesn't go far enough and would slow the path to real reform. The immigrant community is frustrated by the Democrats' foot-dragging however, and their discussions with Rubio are reason enough for Team Obama to worry, before a bill is even written.

IS RUBIO THE MUST-PICK FOR ROMNEY? Ask A.B. returns Monday, April 30. Please join my weekly video Q&A by sending your questions and comments to Thank you.