INDIANAPOLIS (AP) — Former Indiana House Speaker John Gregg remains the only candidate for the party’s 2016 nomination for governor after a potential challenger decided against entering the race.

Tom Sugar was a longtime senior staffer to former U.S. Sen. Evan Bayh and had talked in recent weeks of running for governor.

Sugar said Monday that his possible campaign was discouraged by party leaders and financial backers who don’t want Gregg to face a primary challenge before a possible rematch with Republican Gov. Mike Pence following a narrow 2012 loss.

Sugar says he’ll continue leading efforts to change what he calls Indiana’s overly partisan system of drawing congressional and legislative voting districts.

State schools Superintendent Glenda Ritz and state Sen. Karen Tallian each dropped their bids for the Democratic nomination last month.