2016 presidential hopefuls in the spotlight

New Jersey Gov. Chris Christie insists it's his role as Republican Governors Association chairman that's bringing him to Iowa this week. But he said, "I'm not gearing up to run up for president. I'm gearing up to win as many governor's races as I can this November and then we'll make decisions about running for president after that."

For Christie, the trip will mark a return to the type of public politics for which he was so well known before allegations of a political payback scandal at home enveloped him and prompted a self-imposed lower public profile.

Christie's visit conveys a clear message that he considers himself politically viable, even amid continuing investigations.

"What helps him the most is the fact that he's doing a good job as chairman of the RGA, keeping his nose to that," said Ron Kaufman, a Republican national committeeman.

"It's pretty nice to be asked. It's enormously flattering. But being flattered isn't enough of a reason to run," Christie said Wednesday on CNBC.

Sen. Marco Rubio is moving onto the turf of Democrats by offering a proposal to ease the burden of student-loan debt.

The Florida Republican introduced a bill Wednesday with Sen. Mark Warner, a Virginia Democrat, to establish a universal system of federal student loan repayment based on the borrower's income.

It's a subject that's also gotten attention from Democrat Hillary Clinton and Jeb Bush, the former Republican Florida governor.

"Should Rubio decide to run for president, it would serve him well," said Republican strategist Ron Bonjean.

Rubio plans to introduce more legislation and release a series of white papers before the end of the year on other domestic issues. He's already been making speeches on foreign policy.

Massachusetts Sen. Elizabeth Warren told a group of young Democrats Wednesday that the political system was "rigged" by powerful lobbyists and the wealthy and made an impassioned case for reducing burdensome student loans.

Warren has repeatedly denied interest in running for president, but jousting among liberal Democrats suggests there's interest in an alternative to Clinton.

Maryland Gov. Martin O'Malley appears to be facing the consequences of sharply challenging the Obama administration's efforts to deal with an influx of immigrant children who have crossed into this country unaccompanied.

O'Malley, a Democrat, spoke to reporters last week about the need for compassion. And he said that the government should not "summarily send children to death" by forcing them to return home. Within hours, O'Malley said he received a phone call from a White House official.

By Tuesday, details of that private conversation leaked to reporters — and not from Maryland's capital. The source of those comments painted O'Malley as a hypocrite: The governor didn't want immigrants returned to their home countries, the source said, but refused to shelter them in his state.

O'Malley said Wednesday that his comments had been misconstrued, and he is "absolutely" willing to have the children sheltered in Maryland.