OLYMPIA ­— Democratic state Rep. Mary Helen Roberts will not seek re-election, saying she’s ready for a break from politics after a decade in office and 40 years of political activity.

Roberts told House leaders Friday and was expected to announce her decision to residents at a series of town hall sessions on Saturday.

“I sense it’s the right time,” she said in an interview before the community meetings. “It just feels like it’s enough.”

Roberts is in her fifth term representing the heavily Democratic 21st Legislative district in south Snohomish County. It encompasses Edmonds and unincorporated areas abutting Lynnwood and south Everett, including Paine Field.

Roberts, 67, a former trustee for Edmonds Community College, ran a small business importing folk art from China and Southeast Asia before she was elected to the Legislature in 2004. She’s been re-elected four times by comfortable margins.

As of Friday, she faced no opposition for another term. Now, Democrats and Republicans who would never contemplate challenging an incumbent are certain to consider running for the seat.

In the Legislature, Roberts serves as vice-chairwoman of the House Public Safety Committee. She’s also a member of the Early Learning &Human Services, Judiciary and powerful Rules committees.

In her tenure, she’s focused on policies rather than building a political career. One reason is she was 57 when she arrived in office, which is later than most first-time office-holders.

“If I had been elected in my early 30s I might have been full of congressional ambitions,” she said. “Once I got here I wanted to focus on doing a good job.”

Over the course of a decade, she’s kept her sights trained on funding education programs and human services. As a liberal Democrat, that means she’s not shied away from supporting the creation of new revenue from closing tax breaks or even raising some taxes.

She’s also worked tirelessly to improve the plight of children and to steer people with mental health or substance abuse problems into treatment rather than jail — and to find ways of helping those behind bars survive when they get out.

“My goal with a number of bills is trying to reduce the growth in the prison population while focusing on community safety,” she said.

For example, one of her first bills signed into law created a panel that worked on ensuring children of incarcerated parents receive services they need, to avoid taking the same path as their parents.

And this year she’s pushing a bill that would allow someone with a drug or alcohol addiction who is arrested for a misdemeanor or gross misdemeanor to be taken to an approved drug treatment provider rather than to jail. It passed the House and awaits action in the Senate.

If it becomes law, this would count as a small success at chipping away at the bigger problem of the state spending too much money to lock up individuals with substance abuse and mental health problems, she said.

Reflecting on her time in office, Roberts said the job of citizen legislator has proven more intense than she envisioned and today is pretty much a full-time gig.

She is the parent of twin daughters who are graduates of Kamiak High School in Mukilteo.

Jerry Cornfield: 360-352-8623; jcornfield@heraldnet.com.