WASHINGTON (Reuters) – The nominee to be the next U.S. Army secretary told lawmakers on Thursday that cutting the size of the force had increased the risk to American security and that further reductions would require a rethinking of the Army’s role and priorities.

Eric Fanning, a longtime senior defense official who would be the first openly gay military service secretary, told his confirmation hearing that reducing the Army to 450,000 troops by 2018 from about 490,000 currently, was manageable but would increase the risk to national security.

The Pentagon is in the process of cutting almost $1 trillion in projected defense spending over a decade under a 2011 deal approved by the White House and Congress.

Cutting the active-duty Army to 420,000 soldiers, which could be required if the spending cuts are not reversed, “would require a whole new set of assumptions and guidance on what the Army is supposed to do and what its priorities should be,” said Fanning, who would replace Army Secretary John McHugh, who stepped down several months ago.

Republican presidential candidates have blasted the cuts, promising more military spending to confront international threats including Islamic State.

Fanning would bring unique experience to the job because he has served at senior levels in all three branches of the U.S. armed forces, including stints as acting Air Force secretary and acting Army secretary.

Members of the Senate Armed Services Committee were largely positive about Fanning’s nomination, although the panel waited several months to take it up, leading the administration to name him acting Army secretary.

That prompted Republican Senator John McCain, chairman of the committee, to write a letter to the White House in November charging Fanning’s appointment as acting secretary was a violation of a law barring nominees from taking steps that presume they will be confirmed.

While the White House disagreed, Fanning stepped down in deference to McCain’s concerns and has since been preparing for the confirmation hearing.

Advocacy groups said Fanning’s nomination was a significant sign of progress in protecting the rights of gays and lesbians to serve in the world’s most powerful military.

For many years, the U.S. military followed a “don’t ask, don’t tell” policy that allowed gays to serve only if they did not disclose their sexual orientation. It abolished that policy in 2011.

(Reporting by David Alexander; Editing by Peter Cooney)