Sen. Patrick Leahy “was not feeling well” on Thursday and was admitted to the hospital overnight for observation, his office said in a statement.

The most senior Democratic senator, who is in the line of presidential succession, was taken to a hospital in the D.C. area “for tests, as a precaution,” according to his office. Leahy’s doctors recommended he remain overnight.

The Vermont Democrat is retiring at the end of the year after eight terms in the Senate, after deliberating over whether to run for re-election. It’s a career that’s culminated in chairing the Appropriations Committee and serving as Senate pro tempore, a role that places him third in the line of presidential succession.

Leahy also usually opens the Senate, as he did this week for a short session kicking off the National Defense Authorization Act.

Leahy, 82, was briefly hospitalized at the start of Democrats’ 50-50 Senate majority in 2021, then broke his hip this year in a fall. Leahy had returned to his duties this fall and was walking around the Senate hallways in September, chatting up reporters and Senate staffers.

Leahy’s office said it will “offer updates as warranted.” The Senate is now in a recess until after the midterm elections in November. Rep. Peter Welch (D-Vt.) is favored to take Leahy’s seat in a race against GOP candidate Gerald Malloy.

Depending on which party controls the Senate, either Sen. Dianne Feinstein (D-Calif.) or Sen. Chuck Grassley (R-Iowa) is in line to succeed Leahy as Senate pro tem.

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