Tom John will resign as chairman of the Marion County Republican Party once a new chairman is chosen, he announced in a letter sent Tuesday to party members.

John, a lobbyist at Ice Miller LLP, has led the local GOP since 2007. But after Republicans lost all countywide races in November, it was widely expected John would step down.

In the letter, John did not cite the election losses for his departure, but instead the time challenges of the unpaid position.

“It is a difficult job that takes a toll,” he wrote. “For these reasons, I have always believed that a chairman should not remain in the role too long. As I look at my personal priorities and the tremendously important year upcoming, I have decided to resign as your chairman effective upon the election of my successor.”

John’s first year as chairman saw Republicans retake the mayor’s office and regain control of the City-County Council. But, in 2010, Democrats won races for the Marion County prosecutor, sheriff and auditor offices despite a landslide of Republican victories statewide and nationally.

A replacement for John will be elected by party leaders later this month.