Liz Halloran

Republican presidential candidate Mitt Romney continued Tuesday to push back on calls to release more years of tax returns and defended keeping investments in offshore accounts — both issues that have been dogging his run for the White House.

As the presidential campaigns continue to ramp up their attacks (see: felon, liar, outsourcing), the candidates are homing in this week on the country's electoral fertile crescent.

President Obama may have disappointed the NAACP by appearing only via brief video message Thursday at the civil rights group's annual gathering — especially after Mitt Romney had personally taken the stage a day earlier.

But sending in Vice President Biden to stir things up, just 24 hours after Romney was booed while delivering a conservative message meant to resonate beyond the walls of the Houston convention center, seemed to work out just fine for Obama.

Below are President Obama's and Republican challenger Mitt Romney's policies and proposals regarding immigration. NPR will be comparing the two candidates on various issues in the run-up to the November election. If you have suggestions for other issues you'd like us to explore, please leave a note in the comments section below.

DREAM Act:

Obama:

Supports; also endorses letting foreign students stay in U.S. after college graduation.

Republican presidential candidate Mitt Romney's planned speech Wednesday at the NAACP convention in Houston comes at a precarious time for the nation's African-American community.

-- The unemployment rate among blacks is north of 14 percent — more than 5 points higher than the national average.

-- Opponents of GOP-led efforts to require voters in about a dozen states to show identification say the voter ID laws could disproportionately disenfranchise legal black and Latino voters.

When the Supreme Court upheld the central tenet of President Obama's health care law, it meant that several lower court fights on other aspects of the sweeping legislation can move forward.

Those cases, including high-profile lawsuits by Catholic organizations challenging the law's contraception coverage rules, would, obviously, have been affected if the court had found the individual mandate unconstitutional or struck down the law in its entirety.

But with the law intact, the lawsuits — many of them held in abeyance pending the high court's decision — will proceed.

Bloomberg pollster J. Ann Selzer ignited something of a political firestorm this week when her national survey for the news organization showed President Obama leading GOP presidential candidate Mitt Romney among likely voters by 13 points, 53-40 percent.

Most recent polls have shown the race much closer.

Republican presidential candidate Mitt Romney softened his tough primary-campaign tone on immigration, if not his positions, during a speech Thursday to national Hispanic leaders.

In comments to thousands gathered at the National Association of Latino Elected and Appointed Officials in Orlando, Fla., the former Massachusetts governor criticized President Obama's failure to take action on comprehensive immigration reform.