U.S. "deficit hawks" keep up fight despite fading interest

* As deficit declines, so does public interest in it

* Biggest funder of anti-deficit movement doesn't waver

* Some U.S. lawmakers eye measures adding to deficit

By Susan Cornwell

WASHINGTON, Aug 26 (Reuters) - As the U.S. government's budget deficit has declined, so has anxiety about it in Congress and on the presidential campaign trail, but one family and the Washington "deficit hawk" community it bankrolls are unfazed.

Among the capital's many activists, few names are as closely linked to one issue as the Peterson family is with attacking the deficit and the federal debt.

Yet they face a growing struggle to win attention for the cause as the deficit has shrunk to less than a third of its level when President Barack Obama took office, making it a less pressing issue for politicians and the public alike.

The Congressional Budget Office (CBO) said on Tuesday the deficit will likely be $426 billion in fiscal 2015 and decline further to $414 billion in fiscal 2016. That would be its lowest level since 2007. The deficit peaked at $1.4 trillion in 2009.

Nevertheless, Michael A. Peterson, president of a $1-billion foundation set up in 2008 by his father Peter G. Peterson and devoted to fiscal reform, warns that the long-term federal fiscal picture is still dire and vows to fight on.

"The budget is not front and center right now, and there's not a lot of political will in Washington to solve it right now, but I don't think that means that there's a view that this challenge isn't still a major issue," he told Reuters.

"We still have a very significant long-term debt problem."

Increased tax revenues on a strengthening economy, modest budget restraint imposed since 2011, and sharply reduced spending on foreign wars have all helped bring the deficit down.

Still, the CBO projected that the public's holdings of U.S. federal debt - the accumulation of years of deficits - is projected to hit $13.2 trillion this year, up from $12.8 trillion last year, and to rise above $20 trillion by 2025.

(Related graphics: http://link.reuters.com/qup45w and http://link.reuters.com/her45w)

PETERSONS UNDETERRED

"Pete" Peterson, 89, co-founded The Blackstone Group, a major financial firm, in 1985 after serving in the 1970s as U.S. secretary of commerce. He set up the Peter G. Peterson Foundation to address "key fiscal challenges threatening America's future and to accelerate action on them."

Since 2009, the foundation has given $7.6 million to an anti-deficit group called the Concord Coalition, and $6 million to another group, the Committee for a Responsible Federal Budget. These groups were founded in the 1980s and 1990s to advocate for "responsible" fiscal policy.