Mayor Sylvester Turner earned a plurality of votes in all but two voting precincts in the western half of the Inner Loop on Tuesday, gaining ground in the crucial high-turnout area compared to the lackluster tallies he posted there in his campaign four years ago.

That is one of several key takeaways from an analysis of this week’s election returns, which resulted in Turner falling just short of winning outright, and instead heading to a December runoff with trial lawyer Tony Buzbee. A dozen city council races also will go to runoffs.

Another clear takeaway: Buzbee was able to present himself as the most viable alternative to Turner, to the detriment Bill King, a lawyer who narrowly lost to Turner in the mayoral runoff four years ago but who earned a plurality in scarcely a dozen precincts citywide on Tuesday.

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It was unsurprising that Buzbee earned a plurality in conservative city council districts A (Spring Branch), G (the west side) and E (Kingwood and Clear Lake), experts said, nor that Turner easily won districts B, D and K, which are represented by African-American council members.

The most important outcome, Rice University political scientist Mark Jones said, came in District C, the grouping of mostly affluent, left-leaning neighborhoods west of downtown — Oak Forest, Garden Oaks, Timbergrove, the Heights, Montrose, Meyerland — where voters consistently turn out at the highest rates in city elections.

Turner earned just a quarter of the vote in the district in November 2015, and lost the district by 11 points to King in the runoff that December. On Tuesday, however, he earned 49 percent of the vote.

“What C indicates is that Turner was able to win over many people who in 2015 voted for Bill King. I think it’s a combination of Turner being the only viable Democrat people were aware of and then also the realization that King was unlikely to reach a runoff,” Jones said. “And Turner has also had four years to prove himself to those voters and by and large they were satisfied with the result.”

Many voters choose a candidate based on who they expect to reach a runoff, Jones said, even if they might have preferred another candidate, such as King in this case, Jones said.

“Buzbee was able to signal to voters that he was the only viable alternative to Turner,” Jones said, “and what many District C voters showed was, given the choice between Buzbee and Turner, they’d take Turner.”

University of Houston political scientist Brandon Rottinghaus agreed, noting that Turner also increased his vote share noticeably in conservative-leaning District G on the west side, though Buzbee still won a plurality there, 39 percent to Turner’s 31 percent; King earned 20 percent.

“There’s a tremendous incumbency advantage in Houston. People are going to go with the candidate they know, and that was Turner,” Rottinghaus said. “He gets an edge even among conservative-leaning folks who are unsure about King and maybe unwilling to vote for Buzbee.”

Though Houston’s turnout patterns shifted little neighborhood to neighborhood from typical patterns, overall city turnout did drop compared to the November 2015 vote, from 27.4 percent to 22.5 percent.

mike.morrisz@chron.com