US presidential candidate John Kerry has received the official backing of the influential Washington Post.
The Post backed Kerry, but questioned his decisiveness
The paper said the choice was difficult, but that Mr Kerry had the "better approach" on many policies.
The New York Times has already backed the Democrat while papers in Texas and Chicago have endorsed George W Bush.
On Sunday, President George W Bush is campaigning in New Mexico and Texas, while Mr Kerry moves from Florida to New Hampshire.
The Washington Post said: "We believe Mr Kerry, with his promise of resoluteness tempered by wisdom and open-mindedness, has staked a stronger claim on the nation's trust to lead for the next four years."
It accused Mr Bush of "wilful indifference" in ignoring advice on conditions in Iraq after the US-led invasion, and called his financial policies "reckless".
However, it also questioned whether Mr Kerry would be decisive enough in power, given his "zigzags" over Iraq policies.
In the latest campaigning, Mr Bush sought to highlight that issue in Jacksonville, Florida, where he mocked Mr Kerry for first voting for the Iraq conflict and then calling it the "wrong war".
"Senator Kerry seems to have forgotten all that, as his position has evolved during the course of the campaign. You might call it election amnesia," Mr Bush said.
Vice-President Dick Cheney, in New Mexico, said the Soviet Union might still exist and Saddam Hussein
might be dominating the Gulf if Mr Kerry had been president in recent years.
Mr Kerry was in Colorado on Saturday, telling voters: "Vote your hopes, not the fears that George Bush wants you to
feel." He later campaigned in New Mexico.
New campaign ads
In addition to the Washington Post endorsement, Mr Kerry has also won the backing of leaders of America's Muslim community.
A Florida Republican with a "W" Mohican for George W Bush
However, the American Muslim Taskforce on Civil Rights and Elections said the vote for Mr Kerry should be a "protest vote" against the Bush administration.
It said it had "disagreements with Senator Kerry on some domestic and international issues" and criticised him for failing to commit to a broad civil rights agenda.
Both parties have unveiled new ads to attack their opponents.
Mr Bush's shows a pack of wolves prowling menacingly on screen as a female narrator accuses Mr Kerry of being dangerously weak on national security.
Democrat vice-presidential candidate John Edwards described it as a despicable and contemptible attempt to scare Americans.
For their part, the Democrats liken George Bush to an ostrich, with his head in the sand, while comparing Mr Kerry to a soaring eagle.
Election day is 2 November, although millions of voters have already cast their ballots.
About 30 states allow early or absentee votes.
A total of 1.3m Americans had voted in eight battleground states as of Friday, the Washington Post reported.