President Barack Obama is hitting the road again this week with a "Betting on America" bus tour of Ohio and Pennsylvania.

Obama beat Republican John McCain by 11 percentage points in Pennsylvania and 5 percentage points in Ohio in 2008. Now, both states are seen as competitive.

In fact, battleground states abound this year and that makes the race extra expensive since that's where both campaigns and independent groups are plowing big bucks.

Ohio may be the premier swing state. No Republican has ever made it to the White House without carrying Ohio and no Democratic candidate since John F. Kennedy in 1960. Obama has scheduled stops Thursday in the northern Ohio cities of Maumee, Sandusky and Parma.

His Friday tour includes a speech in Pittsburgh. Pennsylvania hasn't gone Republican since backing George H.W. Bush in 1988.

Swing states have vacillated between parties in recent presidential races. Battleground states are where both sides compete heavily, either to win or to force the other side to spend money and play defense.

States that are both swing states and battleground states include: Colorado, Florida, Iowa, Nevada, New Hampshire, North Carolina, Ohio and Virginia. Wisconsin, Michigan and Pennsylvania are battleground states but not swing states.

Obama's two-day jaunt follows a six-state bus tour last month by Republican challenger Mitt Romney. The bus trips are the first of the 2012 campaign for both candidates, with many more likely.

Obama spent Tuesday at the presidential retreat at Camp David, Md., where he's been since Saturday. Romney was at his vacation home in New Hampshire.

On the Fourth of July, Romney will participate in a parade in Wolfeboro, N.H. Obama will lead a citizenship-naturalization ceremony at the White House for service members and then welcome military families to watch the fireworks from the South Lawn.

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