O'Brien: Trump transferring power is not on the table "at this point"

President Trump handing the powers of the presidency to Vice President Pence is "not something that's on the table at this point," White House national security adviser Robert O'Brien told CBS' "Face the Nation" on Sunday.

Driving the news: The president "feels very well" and will remain at Walter Reed hospital, where he has been since Friday, for "at least another period of time," O'Brien said.

• This comes after White House Chief of Staff Mark Meadows told Fox News on Saturday night: "[H]e's made unbelievable improvements from yesterday morning, when I know a number of us, the doctor and I, were very concerned. ... He had a fever and a blood oxygen level that dropped rapidly."

O'Brien acknowledged the possibility of Trump's condition deteriorating "just like it could happen to anybody, but we're prepared."

• "We have a great vice president. We have a government that is steady."
• "The government's doing well, the president's doing well, and I'm not going to address hypotheticals, but we have plans for everything."

How it works: Under the 25th Amendment, the vice president has authority to step in if the president gives written notice to congressional leadership that he is unable to discharge the power and duties of his office.

• President Reagan briefly handed his duties to Vice President George H.W. Bush when he went under anesthesia for a precancerous colon procedure. President Bush transferred his authorities to Vice President Cheney in 2002 and 2007, both during colonoscopies.
• "If both the president and vice president are very sick but functioning, they can delegate decisions to subordinates," Jonathan Turley, a professor of law at George Washington University, told Axios' Hans Nichols early Friday.
• "Actual succession under the 25th Amendment only kicks in with an effective vacancy due to death or complete incapacity," Turley said.

Go deeper: A look at the presidential chain of command