Democratic presidential candidate John Kerry has criticised President George W Bush's decision to bring back up to 70,000 US troops based abroad.
Military strategy is a key plank of both presidential campaigns
In a speech to the Veterans of Foreign Wars (VFW) in Cincinnati, Ohio, he said the US needed to be working in tandem with foreign allies more than ever.
Mr Kerry said he would also fight a "smarter, more effective war on terror".
He promised 40,000 extra troops, twice as many army special forces, and a better welfare system for veterans.
Ohio is seen as a key battleground state and correspondents say Mr Kerry is keen to win the support of veterans.
He made much of his Vietnam record, his membership of the VFW, and his history of fighting for military causes.
"When I am president you will have a true brother in arms," he told them.
He was given a standing ovation at the beginning and end of the speech - which he rounded off with a salute to his uniformed audience.
Mr Bush addressed the same organisation on Monday, telling them he planned to redeploy or recall up to 70,000 troops in Asia and Europe - many in former Cold War hotspots - so they are ready to face "the challenges of the future".
He slammed what he described as Mr Kerry's plans to reduce force numbers in Iraq during the first six months of his presidency, should he win.
But on Wednesday Mr Kerry said the president's withdrawal plan was misguided.
"Nobody wants to bring troops home more than those of us who
have fought in foreign wars, but it needs to be done at the right
time and in a sensible way. This is not that time or that way," he said.
"Why are we unilaterally withdrawing 12,000 troops from the
Korean Peninsula at the very time we are negotiating with North
Korea - a country that really has nuclear weapons?" he added.
He said the move risked alienating US allies at a time when the support of such allies is needed in the global fight against al-Qaeda.
Military strength is a key issue for the Bush and Kerry campaigns in the run-up to November's presidential elections.
Meanwhile, the candidates' efforts to claim the high ground in terms of their military record is continuing.
On Tuesday, Republican Senator John McCain called on Mr Kerry to denounce radio ads made by a pro-Kerry group which accuse Mr Bush of dodging front-line service in Vietnam.
"I agree with Senator McCain that the ad is inappropriate," Mr Kerry said in a statement released by his campaign.
"This should be a campaign of issues, not insults."