(NBC NEWS) -- President Obama's nominee to head the CIA is defending the use of unmanned drones to kill terror suspects.
He goes before a Senate panel today, just as the administration decided to release a classified memo justifying their use.
Lawmakers say they've been asking for that memo for two years and think it's no coincidence they're getting it now - right before questioning the President's top counterterrorism advisor.
In written answers to the Senate Committee he'll face today, John Brennan says drone strikes on terror suspects are rare, but legal.
On the eve of his confirmation hearing to head the CIA, the White House released to lawmakers a classified memo justifying their use. "We have a high confidence that they're being done for the right reasons in the right way," said White House Press Secretary, Jay Carney.
"What qualifies as an imminent threat that would warrant taking a life without any kind of proceeding, or any kind of review, by anybody else?" said Prof. Stephen Saltzburg, GW University Law School.
At least 11 states are trying to limit the use of drones.
40 federal agencies use them to patrol the border, for search and rescue, and to monitor hostage situations like the kidnapping last week in Alabama. "It can be used to save lives." Gretchen West, Association for Unmanned Vehicle Systems International.
But the question is whether it should it be used to kill Americans suspected of working with Al Qaeda overseas. "If you've joined the enemy overseas, you've joined the enemy, and we're going to fight the enemy overseas," said Rep. Mike Rogers, (R) Michigan.
Even some Democrats like Senator Ron Wyden say the memo doesn't adequately explain when the government has the legal right to kill an American.
Brennan will also face questions today on his role in controversial interrogations used by the Bush Administration. Brennan says he had concerns and objected.