President Barack Obama and Republican challenger Mitt Romney are both campaigning Tuesday in crucial battleground states. Call it a taste of things to come - an appetizer for the main course in September and October with the general election scramble.

The president holds a roundtable with a family in Cedar Rapids, Iowa, followed by a speech at a nearby community college. Romney's in Grand Junction, Colorado, holding a town hall in Grand Junction. Both states are in the center divide along each campaign's highway to 270, the number of electoral votes needed to clinch the presidency. For each candidate, winning the state they are visiting Tuesday would be a major bonus in their electoral game plans.

George W. Bush won both states in his 2004 re-election victory over Sen. John Kerry, the Democratic nominee. But four years later Obama took both states in his White House victory over Sen. John McCain, winning Colorado by nine points and carrying Iowa by ten points.

The most recent polls indicate that it's basically all knotted up in both states. An NBC News-Marist survey conducted in late May in Colorado at Obama at 46% and Romney at 45%, with 8% unsure. An NBC News-Marist poll conducted the same period in Iowa indicated the race deadlocked at 44%, with one in ten undecided.

Both states are seeing a flood of campaign commercials on the airwaves. Nearly $9 million has been spent to run ads in Colorado. The Obama campaign has outspent the Romney campaign by a $4.2 million to $1.7 million margin, but when independent advocacy group ad spending is factored in, the number are a bit closer, with nearly $5.6 million in ad spending on the Democratic side and nearly $3.4 million spent on the Republican side.

The figures come from data provided to their clients by Kantar Media/Campaign Media Analysis Group, which tracks political ad spending on broadcast TV and national cable. The data covers the period from April 10 through May 24. April 10 is the day former Sen. Rick Santorum of Pennsylvania suspended his presidential campaign. Santorum was former Massachusetts Gov. Mitt Romney's main rival for the Republican presidential nomination, and when he left the race, Romney became the presumptive GOP nominee.

In Iowa, just over $9.2 million has been shelled out by both sides to run spots. The Obama campaign has outspent the Romney campaign by a more than two to one margin, but when the independent groups are factored in, total ad spending by the Republican side comes to $5.4 million, more than a million and a half dollars than the Democratic side has spent to put up commercials.

"It's basically yin-yang, which is catchy for short-term purposes, but more significant is that once again, as in 2008, Democrats must be looking at data showing, at least for now, that Colorado is more of a reach for them and Iowa considerably less so," CMAG Vice President Elizabeth Wilner tells CNN.