Democrats have lacked an outright majority this week in the Senate as a number of temporary absences complicate their ability to confirm Joe Biden's nominees and give Republicans an easier time sending legislation to the president's desk.

Four senators have missed all of their votes this week, three Democrats and one Republican, underscoring just how tenuous the 51-49 Democratic control of the upper chamber is.

Sen. Dianne Feinstein (D-CA) has left Washington to deal with a “health matter,” according to a spokesperson, and it's not clear when she'll be back for Senate votes. “She hopes to return to Washington soon,” her office said on Wednesday.