The decade-long splurge on intelligence spending in the United States appears to have hit its high-water mark.

The nation spent $54.6 billion on national spy agencies and programs in the fiscal year that ended Sept. 30, excluding spending on military intelligence programs, according to figures released by the nation’s intelligence director.

James Clapper, director of national intelligence. (Melina Mara — The Washington Post)

The Obama administration said in February that it had asked for $55 billion for spy agencies for the upcoming fiscal year. Yet with repeated warnings about pending budget cuts, it appears doubtful that the intelligence community will collect that amount in full.

“If today’s number isn’t the absolute apex, it’s definitely within spitting distance from it,” said a congressional aide involved in intelligence budget deliberations.

Senior members of Congress, grappling with vast, government-wide deficits, have signaled they will look for budget cuts at spy agencies, even while warning against reductions that go too far.

Director of National Intelligence James Clapper has said imposing cuts on agencies that have grown accustomed to generous increases every year will be a “litmus test” of his job.

The trajectory on spy spending has been breathtaking since the Sept. 11 attacks. Budgets more than doubled during a 10-year span in which the CIA and other spy agencies were charged with tracking al-Qaeda and staying abreast of the intense intelligence demands associated with two distant wars.

The contrast is even greater when compared with intelligence budgets that cratered in the aftermath of the Cold War. In 1994, for example, a House subcommittee mistakenly disclosed that the national intelligence budget for that year was $16.3 billion.

These days, that figure would barely cover the bills for the largest spy service, the National Security Agency, let alone leave enough change for the other 15.

Intelligence spending on military programs may already be receding. The Defense Department said Friday that military intelligence spending reached $24 billion for fiscal 2011, down from $27 billion in the previous fiscal year.