MORRISVILLE, N.C. (AP) -- Wooing young voters, President Barack Obama is on a blitz to keep the cost of college loans from soaring for millions of students, taking his message to three states strategically important to his re-election bid. By taking on student debt, Obama is speaking to middle-class America and targeting an enormous burden that threatens the economic recovery.

Before Obama got his road trip under way, Republican opponent Mitt Romney found a way to steal some thunder from the president's campaign argument: He agreed with it.

The competitors are now on record for freezing the current interest rates on a popular federal loan for poorer and middle-class students. The issue is looming because the rate will double from 3.4 percent to 6.8 percent on July 1 without intervention by Congress, an expiration date chosen in 2007 when a Democratic Congress voted to chop the rate in half.

Obama is heading to campuses in the South, West and Midwest to sell his message to colleges audiences bound to support it. As he pressures Republicans in Congress to act, he will also be trying to energize the young people essential to his campaign - those who voted for him last time and the many more who have turned voting age since then.

The president speaks Tuesday at the University of North Carolina at Chapel Hill and the University of Colorado at Boulder, and then the University of Iowa on Wednesday. All three universities are in states that Obama carried in 2008, and all three states are considered among the several that could swing to Obama or Romney and help decide a close 2012 election.

Both campaigns are fighting for the support of voters buried in college debt. The national debt amassed on student loans is higher than that for credit cards or auto loans.

The Federal Reserve Bank of New York has estimated about 15 percent of Americans, or 37 million people, have outstanding student loan debt. The banks put the total at $870 billion, though other estimates have reached $1 trillion. About two-thirds of student loan debt is held by people under 30.

Obama, previewing the message he will give at all three colleges, said over the weekend that allowing the interest rates to double this summer would hurt more than 7 million students. The White House said it would cost students $1,000, based on the average amount borrowed a year ($4,200) and the average time it takes to pay the loan (12 years).

"That would be a tremendous blow," Obama said. "And it's completely preventable."

Romney agreed with that conclusion even in the midst of blasting Obama's economic leadership. "Given the bleak job prospects that young Americans coming out of college face today, I encourage Congress to temporarily extend the low rate," Romney said in a statement.

White House spokesman Jay Carney said the administration welcomed support for freezing the interest rate from any Republican. But Carney said it was "ironic" that a Republican could both back the interest rate freeze and support a budget proposal from Rep. Paul Ryan, R-Wisc., that the White House says would double the student loan interest rate freeze.

Romney has said he is "very supportive" of the Ryan budget.

With Romney all but certain to sweep the five Republican presidential primaries being held Tuesday, the former Massachusetts governor planned a definitive pivot toward the general election, with a speech in New Hampshire titled "A Better America Begins Tonight."

The student loan rate freeze Obama and Romney are championing amounts to a one-year, election-year fix at a cost of roughly $6 billion. Congress seems headed that way. Members of both parties are assessing ways to cover the costs and win the votes in the House and Senate, which is far from a political certainty. All parties involved have political incentive to keep the rates as they are.

Obama carried voters between the ages of 18-29 by a margin of about 2-to-1 in 2008, but many recent college graduates have faced high levels of unemployment. That raises concerns for the president about whether they will vote and volunteer for him in such large numbers again.

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AP Education Writers Kimberly Hefling and Justin Pope contributed to this report.

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