Grassley is the president pro tempore of the Senate, meaning he presides over the Senate in the absence of Vice President Mike Pence and is third in line to become president, behind Pence and House Speaker Nancy Pelosi. The president pro tempore is the senator in the majority party who has served the longest.
By missing votes Tuesday, Grassley broke a 27-year streak of not missing a Senate vote. According to his office, the last time he missed a vote was in 1993, when he was in Iowa assisting with relief efforts after severe flooding.
Grassley was first elected to the U.S. House in 1974 and then to the Senate in 1980. He is the chairman of the Senate Finance Committee and is expected to become the top Republican on the Senate Judiciary Committee when a new Senate session begins in January.