The Democrats' as yet unofficial presidential candidate, Mr John Kerry has said he can fight a more effective war on terror than President George W Bush.
Portraying himself as a viable alternative as commander in chief and seeking to erode Bush's advantage on homeland security, Mr Kerry told a rally in Philadelphia that "the world is waiting" for the United States to lead.
On the eve of his arrival at the Democratic National Convention in Boston, where he will formally accept his party's nomination as Mr Bush's opponent in the November election, Mr Kerry said the United States "simply must act, not as partisans, but as patriots."
"We understand the threat," the decorated Navy veteran said earlier as he stood in front of the battleship Wisconsin on the Norfolk, Virginia waterfront.
"We have a blueprint for action. The only thing we don't have is time. We need to do it now.
Leadership requires that we act decisively," he said. "Back-pedaling and going slow is something America can't afford."
Mr Bush has so far focused his re-election campaign largely on the argument that he has made America safer since September 11 and has maintained an advantage in the polls over Mr Kerry on the issue of homeland security.
Mr Kerry's supporters have been singing his praises at the Boston convention, where former presidents Mr Bill Clinton and Mr Jimmy Carter said the decorated war veteran would develop a more sophisticated foreign policy that would improve the US's esteem internationally while strengthening the country's defences.
Last night, Massachusetts senator's wife, Mrs Teresa Heinz Kerry haield her husband's values, saying his leadership would unite a divided America and restore credibility to the White House.
On the second night of the Democratic convention, Mrs Heinz Kerry described her husband as a fighter who would vigorously defend America, reclaim the country's moral bearings and "always be the first in the line of fire."