SAN FRANCISCO (AP) -- The acrimonious presidential campaign is easing back into action after a weekend pause for the nation to absorb the shock of a horrific mass shooting at a Colorado movie theater.

The massacre stalled a race for the White House that has become increasingly heated in recent weeks. President Barack Obama, Republican rival Mitt Romney and their advisers are now weighing how soon after the shootings to resume their harsh attacks or whether to temper the tenor of the campaign.

Both campaigns were keeping their largely negative television advertisements off the air this week in Colorado, a key battleground state. The Obama campaign says it won't advertise in Colorado for the rest of the week and the Romney campaign says its ads in the state are "down until further notice."