Republican challenger Mitt Romney, slipping in the polls in critical battleground states, has opened an intense campaign focus in three of them with a rally in Colorado, before he heads to Ohio for a three-day bus tour and ends with a stop in Virginia.
President Barack Obama won all three of those states in the 2008 election that swept him into the White House.
With about six weeks remaining before the November 6 election, the handful of so-called swing or battleground states appear likely to determine the outcome of what has been an extremely close contest between the pair.
Those states become even more critical to the Republican candidate as recent polling has shown Mr Obama opening a lead in many of them.
The US president is not chosen by the nationwide popular vote but in state-by-state contests. While most states reliably vote for the candidate of one party or the other, swing states like Colorado, Ohio, Virginia and five others are seen as toss-ups.
Mr Obama entered the weekend with polls showing him in a near tie with Mr Romney nationally. But a new Wall Street Journal/NBC News/Marist Poll showed the president with leads among likely voters of eight percentage points in Iowa and five points each in Colorado and Wisconsin, all battleground states.
Polls published earlier this week pointed to leads for Mr Obama in Virginia and Ohio. While he and the Republican are neck-and-neck in North Carolina, Mr Obama has an edge in Florida and New Hampshire.
With those factors pressing hard on Mr Romney, he is intensifying his swing-state campaigning to counter criticism from Republican heavyweights that his bid for the nation's highest office is mismanaged and misdirected.
Mr Romney's rally at a Denver-area high school in Colorado represents his first public event of the weekend. As the November vote draws near, he is also facing pressure to spend less time raising money and more time explaining his plans to voters in swing states.
The schedule shift comes in the last full week before the presidential debates move the campaign into a new phase - one which Romney advisers suggest could prove pivotal following several weeks marked by negative attention, mis-steps and Republican concerns.