"Those folks don't have a lot of responsibilities," Obama told a rare news conference at the White House, his first since October.
"They are not commander-in-chief. And when I see the casualness with which some of these folks talk about war, I'm reminded of the costs involved in war ... in terms of sending our young men and women into battle, and the impact that has on their lives, the impact it has on our national security, the impact it has on our economy."
Obama's remarks came two days after he addressed a pro-Israel lobby group and delivered a dire message to Iranians, warning them that the U.S. would use force if necessary to prevent Iran from obtaining nuclear weapons.
"I will take no options off the table, and I mean what I say," Obama told the American Israel Public Affairs Committee on the eve of a White House meeting with Israeli Prime Minister Benjamin Netanyahu.
Obama denied on Tuesday he was softening that stance, assuring reporters he stands behind Israel but has no interest in engaging in pro-war bluster to score political points.
"This is not a game, and there is nothing casual about it," he said.
Sanctions against Iran must be given time to take hold, he added, beseeching the international community, as well as legislators at home, to be patient.
"Iran is feeling the bite of these sanctions in a substantial way," he said.
He added that if his Republican foes would like to embroil the nation in yet another rashly launched war, they should let Americans know.
"One thing that we have not done is we haven't launched a war," he said.
"If some of these folks think that it's time to launch a war they should say so, and they should explain to the American people exactly why they would do that and what the consequences would be. Everything else is just talk."
Both Republican presidential hopefuls Mitt Romney and Rick Santorum assailed Obama's policies on Israel and Iran earlier in the day during their own addresses to AIPAC. Republicans have been attempting to woo Jewish voters, who voted overwhelmingly for Obama in 2008, by painting the president as weak on Iran.
In an opinion piece in the Washington Post on Tuesday, Romney also accused Obama of "fretting" about what to do while Iran beavers away at developing a nuclear program. He also called Obama the most "feckless" president since Jimmy Carter, a popular whipping boy for Republicans.
"Good luck tonight," Obama said to guffaws when asked what he thought of Romney's remarks. "Really."
Ten states were holding nominating contests on so-called Super Tuesday in the biggest single day in the Republican presidential race. More than 400 delegates are up for grabs and polls suggested Romney was poised to take most of them.
Obama took questions in the crowded James S. Brady briefing room for 45 minutes, primarily on Iran, Israel and Syria. He described the bloody crackdown on pro-democracy protesters in Syria as "heartbreaking" but said unilateral action against the country would be a mistake.
Apart from foreign policy questions, Obama also weighed in on the controversy dogging Rush Limbaugh this week.
The conservative radio star is still losing advertisers after calling a third-year Georgetown University law student a "slut" and a "prostitute" for her congressional testimony in support of Obama's contraception policies.
"All decent folks can agree that the remarks that were made don't have any place in the public discourse," Obama said before making reference to his own two daughters.
"I thought about Malia and Sasha, and one of the things that I want them to do as they get older is to engage in issues they care about, even ones that I may not agree with them on," he said. "I want them to be able to speak their minds in a civil and thoughtful way and I don't want them attacked or called horrible names because they're being good citizens."
He made a phone call to Sandra Fluke, Obama added, to show his support. Limbaugh and Newt Gingrich, also vying for the Republican presidential nomination, ridiculed him for the call last week.
"I wanted Sandra to know that I thought her parents should be proud of her," Obama said.
He wouldn't weigh in on suggestions that the Republican party has declared war on women with its recent fight against his administration's contraception policies because of claims they violate religious liberties.
But he added the Democratic party has more to offer women.
"Women are going to make up their own mind in this election about who is advancing the issues that they care most deeply about," he said, adding women are not "single-issue" voters.
"But I believe that Democrats have a better story to tell to women about how we're going to solidify the middle class and grow this economy."