In a speech this month at the Ronald Reagan Presidential Library in California, House Armed Services Committee Chairman Howard P. “Buck” McKeon sought to project defiance in the face of multiple challenges, both from enemies abroad and what he sees as misplaced priorities on the homefront.

Despite a U.S. strategic outlook that is “a tangled mess,” McKeon (R-Calif.) said, “I am not so pessimistic.”

In his third year as chairman of the Armed Services panel, a perch that should give him a key role in steering the nation’s ever-growing military machine, McKeon is instead fighting a defensive action on two fronts — against proposed cuts to the Pentagon budget and a rising tide of pessimism, among the public and his colleagues, about the American mission in Afghanistan.

“Overall we’re doing well, we’re making good progress,” McKeon said of Afghanistan in an interview Monday. “The problem I see is that the media . . . they don’t focus on the good things that happen, they only focus on the negative.”

McKeon acknowledges that there has been plenty of negative fodder of late — from the alleged killing of 17 Afghans by Army staff Sgt. Robert Bales this month, to the burning of Korans by U.S. soldiers in February and subsequent attacks that killed a half-dozen Americans.

McKeon is not arguing that those incidents are getting too much attention. But he says the effects of those stories have been made worse because more positive developments — such as schools being built — aren’t getting covered. And, he contends, that’s partly President Obama’s fault.

“I’m concerned that the president hasn’t done more using his megaphone just to keep the American people up to date on what’s going on, so when you get into a problem situation like this they can put it in the proper context,” McKeon said.

At a hearing last week on Afghanistan, McKeon suggested that with “friend and foe alike knowing that the U.S. is heading for the exits, our silence is likely viewed as a preamble to retreat.”

(Obama has said the United States is fulfilling its objectives in Afghanistan and is “starting this drawdown [of troops] from a position of strength.”)

In a Gallup poll taken just after the 17 Afghans were killed, 50 percent of respondents said the United States should speed up its withdrawal of troops from Afghanistan from the current target of the end of 2014. Only 21 percent said the troops should remain “as long as it takes” to accomplish American goals.

That pessimism has reached Capitol Hill. “There are some that are growing impatient,” McKeon said of his colleagues.

On the campaign front, McKeon endorsed former Massachusetts governor Mitt Romney for president last June.

“I feel real good about the direction he’s taking . . . toward the military,” McKeon said, though he has not advised the candidate directly on national security issues.

But McKeon is aware that military matters are not preeminent this election year. The lawmaker said he took a poll in his Southern California district a few months ago and he found, not surprisingly, that the economy and jobs were the most important issues by a wide margin.

“Defense was very, very low,” he said, adding that those numbers could be explained one of two ways: “You can think people don’t care about defense, or you can assume they’re feeling pretty good because we have a strong defense. . . . But one attack on the homeland would turn those numbers around overnight.”

Not surprisingly, McKeon strongly dislikes Obama’s fiscal 2013 budget proposal, which would cut Pentagon spending by 1 percent compared with 2012, and praises that of House Budget Chairman Paul Ryan (R-Wis.).

“I think he’s realistic” about defense spending, McKeon said of Ryan. “He’s made an attempt to do something about sequestration.”

As part of last year’s Budget Control Act, lawmakers agreed to billions of dollars in automatic defense spending cuts beginning next year if the deficit-cutting “supercommittee” couldn’t strike a deal. McKeon backed the measure at the time.

“When we voted for it we were assured that sequestration was so bad it couldn’t possibly happen,” McKeon said. “The supercommittee would be forced to do something. They didn’t.”

Ryan’s budget suggests replacing automatic defense cuts with more domestic cuts, and McKeon has proposed cutting the federal workforce instead. But McKeon worries that too many members, other than those on his committee, are taking the threat of sequestration too lightly.

“It’s hard to get the word out to everybody else,” McKeon said. “I think a lot of people tend to assume it will get fixed.”

Some Democrats have told McKeon they think sequestration and other thorny spending issues will be addressed in a lame-duck session after November’s elections, a prospect he views as highly unrealistic.

“It just doesn’t make sense,” he said. “We should be addressing these problems now.”