For the first time in more than four decades, Congress will examine the president's authority to wage nuclear war.
"To be clear, I would not support changes that would reduce our deterrence of adversaries or reassurance of our allies".
The Senate Foreign Relations Committee held a hearing on the president's powers to launch a nuclear strike, and chairman Bob Corker (R., Tenn.) said it was not specifically about Trump.
At an October 30 Senate Foreign Relations panel hearing, lawmakers pressed Defense Secretary Jim Mattis and Secretary of State Rex Tillerson about policies for using nuclear weapons.
Corker said last month that Trump has set the United States "on a path to World War III" in his dealings with North Korean leader Kim Jung Un.
Congress needs to explore "the realities of this system", he said.
The president, as commander in chief, is the sole arbiter or whether to use the US nuclear arsenal - an issue that hasn't been debated at the congressional level in more than 40 years.
"This is a system controlled by human beings. nothing happens automatically", he said, adding that the USA military does not blindly follow orders and a presidential order to employ nuclear weapons must be legal.
"No one can veto the president's decision", Blair said.
Senator Ben Cardin, a Maryland Democrat, said he's been receiving "more and more questions" during town hall meetings with constituents about whether the president can order a nuclear attack without any controls. The measures, though, have not advanced in the Republican-controlled Congress. That position followed Trump's threat of "fire and fury like the world has never seen" if Pyongyang continues its nuclear missile program.
At Tuesday's hearing, senators will hear from C. Robert Kehler, a retired Air Force general who served as commander of the United States Strategic Command; Peter D. Feaver, a political science and public policy professor at Duke University; and Brian McKeon, former acting under secretary for policy at the Defense Department.
Corker has become a vocal critic of President Donald Trump and referred to the White House as an "adult day-care center" in a Tweet.
The hearing is one in a series the committee is holding on war making and foreign policy.
Corker said afterward that he expects the committee to take up a new military-force authorization resolution "fairly soon".