SACRAMENTO, Calif. -

A Democratic state senator from the Central Valley has resigned unexpectedly, dropping Democrats below the two-thirds threshold they need to pass tax changes or override vetoes.

Sen. Michael Rubio from Shafter, which is near Bakersfield, announced his resignation Friday to take a government affairs job with Chevron Corporation.

Rubio did not immediately respond to a request for comment, but Greg Schmidt, secretary of the Senate, confirmed his resignation letter to The Associated Press.

In the letter, the first-term senator said the job of a legislator kept him away from his wife and two daughters. He also noted that his youngest child has special needs.

With two Democratic-leaning seats already vacant, Rubio's resignation temporarily drops Democrats to 26 seats in the Senate, one shy of a supermajority.