* Cutting 'earmarks' could save money
* Cost growth on Lockheed F-35 is unacceptable
* Incoming Republicans committed to cut spending (Adds quotes from McCain and House Republican McKeon)
By Andrea Shalal-Esa
WASHINGTON, Nov 15 (Reuters) - Senator John McCain, the top Republican on the Senate Armed Services Committee, said billions of dollars could be saved from the U.S. defense budget by cutting lawmakers' pet projects, known as earmarks, and fixing troubled arms programs.
McCain told a foreign policy forum on Monday that he is confident Defense Secretary Robert Gates will be able to cut $100 billion from the defense budget over the next five years to fund personnel costs and keep weapons programs on track.
He cited several big arms programs that were over budget and behind schedule, saying they presented further opportunities to save money.
He said the Lockheed Martin Corp (LMT.N) F-35 fighter program, now projected to cost $382 billion, was one example, saying it was "unacceptable" that the cost of each fighter jet was now double what was initially planned.
McCain also said he worried a lot about the rise of protectionism and isolationism in the Republican Party, and whether that could lead to an erosion of support for the war in Afghanistan, particularly given calls by some newly elected members of Congress to cut defense spending.
"There's no doubt that this new group of Republicans have come in with a commitment that would take a weed ax to spending," McCain told an event hosted by the Foreign Policy Initiative." I'm not sure that we could say that everything in defense is sacrosanct while the rest of these cuts in education and social programs, etcetera, are taking place."
Representative Howard "Buck" McKeon, who is expected to become the next chair of the House Armed Services Committee, told the same forum later it would be a mistake to cut overall U.S. defense spending at a time when the country was engaged in two wars.
He applauded Gates' efforts to find savings, but said he worried the Obama administration and "some in Congress" would not allow those savings to be reinvested into modernization and personnel accounts.
"A defense budget in decline portends an America in decline," McKeon told the forum, saying that view had strong bipartisan support. "It will undermine our ability to project power, strengthen our adversaries and weaken our alliances."
Two leaders of a U.S. presidential commission released a plan last week that would cut the overall defense budget by $100 billion by 2015, using the savings to reduce the U.S. budget deficit instead of reinvesting the money to pay for troops and weapons programs as Gates has planned.
McKeon said he would oppose such cuts.
"Cutting defense spending amidst two wars is a red line for me and should be a red line for all Americans," he said, citing a recent poll by The Hill newspaper that showed that 60 percent of Republicans and 53 percent of independents would not support cuts to defense and homeland security spending.
McKeon also noted that several of the incoming Republican lawmakers had served in the military and were unlikely to support big cuts in defense spending. (Reporting by Andrea Shalal-Esa; editing by John Wallace and Andre Grenon)