Montgomery County Council members from left, Craig Rice, George Leventhal, Roger Berliner, Marc Elrich, Nancy Floreen, Tom Hucker, Sidney Katz, Nancy Navarro and Hans Riemer are sworn in at Richard Montgomery High School in 2014. (Katherine Frey/The Washington Post)

A majority of seats on the nine-member Montgomery County Council would change hands in 2018 if a proposed charter amendment for term limits is placed on the November ballot and approved by voters.

The proposition, authored by Republican activist Robin Ficker, limits council members and the county executive to three consecutive terms. County officials initially thought the amendment would directly affect four council members: Roger Berliner (D-Potomac-Bethesda) and Marc Elrich (D-At Large) are serving their third term, and Nancy Floreen (D-At Large), and George L. Leventhal (D-At Large) are serving their fourth.

But the amendment defines “term” as both a full term and a portion of one. It means that council member Nancy Navarro (D-Mid-County), first elected in May 2009 to fill the unexpired term of the late council member Don Praisner and then elected to two full terms, is also covered by the measure.

“It was a little bit surprising that it was specific,” Navarro said Tuesday.

If approved, the charter amendment would trigger the largest council turnover in many years.

Robin Ficker, a Montgomery County Republican activist, talks with people to try and get some of the 10,00 valid signatures he needs to place a term-limits proposal on the November ballot. (Jabin Botsford/The Washington Post)

Two new members — Elrich and Berliner — were elected in 2006. Two others, Craig Rice (D-Upcounty) and Hans Riemer (D-At Large) won seats in 2010. In 2014, the most recent election, Tom Hucker (D-Eastern County) and Sidney Katz (D-Gaithersburg-Rockville) won open seats,

Prince George’s County is the only local government in the Washington metropolitan area with term limits; council members and the county executive are limited to two consecutive four-year terms. In 2014, voters narrowly rejected a ballot question that would have extended the limits to three terms.

Virginia limits its governor to four years, and Maryland, to eight years.

But the Prince George’s measure does not count partial terms against the legal limit. Former council member Will Campos (D), for example, won a special election to fill an unexpired term in 2004, then won reelection in 2006 and 2010.

Navarro said she plans to explore the legality of counting partial terms.

“It’s something I want to look into,” she said.

Navarro said she would also “keep my options open” on the possibility of running for county executive. The other four potentially term-limited members — Leventhal, Berliner, Elrich and Floreen — are also said to be consideringthe race.

County Executive Isiah Leggett (D), who is serving his third term, is expected to retire after 2018.

In order to get the term-limits proposal on the ballot, Ficker must submit at least 10,000 valid signatures of registered voters to election officials by Aug. 1.

This is his third attempt to win approval for some form of term limits. A 2004 ballot proposition was defeated 52 percent to 48 percent. Four years earlier, it lost by 54 percent to 46 percent.