US Sen. Patrick Leahy of Vermont was hospitalized Thursday after he felt unwell at his McLean, Virginia, home, his office said.
As a precaution Leahy, 82, was taken to a Washington-area hospital for tests. At the recommendation of his doctors, he was expected to remain in the hospital overnight for observation.
Leahy, the longest-serving sitting senator, is not seeking reelection in November.
By the time his term expires in January 2023, Leahy will have served for 48 years in the Senate.
Leahy has been making a number of public appearances since then.
Leahy was taken to the hospital in January 2021, hours after he had begun presiding over the second impeachment trial of former President Donald Trump. At that time Leahy said he was not feeling well and he was taken to the hospital out of an abundance of caution. After being examined, he was sent home.
Leahy is the last of the so-called Watergate babies, the surge of congressional Democrats elected in 1974 after Republican President Richard Nixon resigned to avoid impeachment.