WASHINGTON - President Obama rejected comparisons on Monday between the war in Afghanistan and the conflict in Vietnam a generation ago, but he expressed concern about "the dangers of overreach" and pledged a full debate before making further decisions on strategy.
The president's comments, in an interview at the White House with The New York Times and CNBC, appeared to be a response to rising unease within his own party in Congress about the possibility of the United States becoming bogged down in Afghanistan.
Asked whether he worried about repeating the fate of President Lyndon B. Johnson, who declined to seek re-election in 1968 as a result of the turmoil over Vietnam, Mr. Obama replied: "You have to learn lessons from history. On the other hand, each historical moment is different. You never step into the same river twice. And so Afghanistan is not Vietnam."
But, he added, "The dangers of overreach and not having clear goals and not having strong support from the American people, those are all issues that I think about all the time."
The president promised to weigh the recommendation of the top commander in Afghanistan, Gen. Stanley A. McChrystal, on whether the United States should commit more troops. But he took issue with assertions that the job of dismantling terrorism networks can be handled by drones and other alternatives to soldiers on the ground.
"I assure you that if that were the case, you wouldn't see 68,000 of our young men and women deployed in Afghanistan," he said.
In the interview, Mr. Obama also addressed the repercussions from his decision late last week to levy new tariffs on tires imported from China. He said that his actions and China's response would not incite a trade war.
"I think it's in China's interests and our interests and the world's interests to avoid protectionism, particularly just as world trade is starting to bounce back from the huge declines that we've seen in the last year," Mr. Obama said.
He said that the decision would give him credibility with his labor union supporters the next time he told them a trade agreement was good for the United States.
Mr. Obama also signaled that he thought the need for a new economic stimulus package may have abated.
"I have a strong inclination not to do" a second stimulus package, he said. "I think that most folks believe that we've now turned the corner where we might actually start seeing some positive economic growth in months to come. As you know, jobs tend to be a lagging indicator; they come last."