With a third Democrat entering the race for Republican Alan DeBoer's Senate District 3 seat, the contest is heating up even before the election year begins. DeBoer, who won a special election for the seat after Sen. Alan Bates died in 2016, says he will decide in January whether to run again. Whoever the nominees are, they will face a hard-fought, big-spending battle for what has historically been a swing district.

District 3 comprises Medford, Ashland, Phoenix, Talent, Jacksonville and part of the Applegate Valley. Each Oregon Senate district encompasses two House districts, in this case District 5, represented by Democrat Pam Marsh, and District 6, represented by Republican Sal Esquivel.

Marsh holds the only district in Southern Oregon with a solid majority of Democratic voters — 21,151 to 11,572. In Esquivel's district, which includes most of Medford, Republicans have an edge, 13,998 to 11,644.

Senate District 3 has 32,795 registered Democrats to 25,570 Republicans. But non-affiliated voters — those registered with no party — outnumber Republicans at 26,723. And the last three elections have been squeakers.

DeBoer won the special election to succeed Bates over Democrat Tonia Moro last year by just 535 votes. Spending in that brief but vigorous race topped $1 million.

Bates survived two down-to-the-wire re-election campaigns to Republican challenger Dave Dotterrer in 2010 and 2014.

The Democrats who have declared so far — former Jackson County Commissioner Jeff Golden, Medford City Councilor Kevin Stine and Ashland physician Julian Bell — all cite health care as a primary issue. Affordable housing and climate change are other concerns likely to emerge during the campaign.

Both major parties in the state see the district as pivotal, and have contributed money and advertising to candidates in past contests. Democrats will be angling to win back District 3 from a Republican with only two years in the job. Republicans will be trying to hold on to the seat. If DeBoer decides against a re-election campaign, that will set off a scramble to come up with a strong candidate.

Given the extreme polarization of American politics, it may be too much to expect a civil, constructive campaign, but voters should demand one. Previous contests have featured negative advertising from both sides of the fence — a tactic that doesn't sit well with Southern Oregon residents. I sincerely hope all the candidates for this pivotal seat will keep that in mind throughout the campaign, but especially after the nominees are selected in the May primary.

Mean-spirited attacks benefit no one, least of all the voters who must make a choice on election day.

— Reach Editorial Page Editor Gary Nelson at gnelson@mailtribune.com.