State Sen. Mark Dion, a former Cumberland County sheriff, has joined a crowded Democratic field running for governor in 2018.

Dion, 62, is a Lewiston native, Portland resident and a practicing attorney who supported the statewide ballot measure that legalized recreational adult-use marijuana last year. He was elected to the Maine House of Representatives in 2010 and served three terms before being elected to the Senate in 2016.

Dion was elected sheriff in 1998 and was re-elected twice before he ran for the Legislature.

“In my life, I have learned that listening sometimes takes more courage than speaking,” said Dion, who announced his intention to run at the Cumberland County Jail. “But a leader must always be ready for that moment, which calls for him or her to break ranks to act in the best interests of all the people of our state. I have made those decisions as a sheriff and I realize how important it will be for a governor to see the difference between popularity and principle in choosing the best course for Maine’s future.”

For months, political insiders had speculated that Dion would join what has become a field of 10 Democrats who will face off in a primary next June.

Other notable candidates include Maine Attorney General Janet Mills, former Speaker of the House Mark Eves, Sanford attorney and Army veteran Adam Cote, former state Rep. Diane Russell of Portland and former state Sen. James Boyle of Gorham.

Dion registered as a candidate Wednesday and is running a privately financed campaign, according to records at the Maine Commission on Governmental Ethics and Election Practices.

He currently serves on the Legislature’s Energy, Utilities and Technology Committee and also has a seat on the special select committee formed to implement the state’s marijuana legalization law.

Scott Thistle can be contacted at:

sthistle @pressherald.com