Sebelius on the 2018 Senate race,

To be sure, 2018 is a ways off. But judging from the emails, tweets and news releases starting to pour in, it’s clear the 2018 political cycle has begun. And U.S. Sen. Dean Heller is in the crosshairs.

National Journal reported last week that Rep. Dina Titus was considering a run against Heller, a Republican. Also mentioned as candidates: state Senate Majority Leader Aaron Ford, D-Las Vegas; former state Treasurer Kate Marshall; and newly elected U.S. Rep. Ruben Kihuen.

It’s no secret why Heller’s seat has attracted so much attention. He barely beat Shelley Berkley in 2012, winning statewide by just 11,576 votes in a race that focused on ethics allegations against Berkley.

But those numbers don’t tell the entire story: Heller, who comes from Northern Nevada, won every county in the state except Clark, Berkley’s base. It was a foreshadowing of 2016, when Democrat Catherine Cortez Masto also lost every county but Clark, yet still managed a nearly 27,000-vote victory over Joe Heck.

Also, 2012 was Heller’s first Senate election after his appointment by Gov. Brian Sandoval in 2011. By now, he’s fully inherited the benefits of incumbency, including the ability to raise money.

But Heller still may be vulnerable to a strategy that aims to boost turnout in Clark County and hold down his advantage in Washoe County. This was U.S. Sen. Harry Reid’s key to victory more than once.

Titus ran for governor back in 2006, losing to Republican Jim Gibbons by nearly 24,000 votes. But Titus, who lives in Las Vegas, beat northerner Gibbons in Clark County by more than 23,000 votes, while Gibbons won every other county, including his base in Washoe.

Although Titus tried to campaign in the rurals, the 2006 campaign taught her the path to Democratic victory in Nevada doesn’t go anywhere near those counties. If Titus does decide to run, she knows she must spend most of her time campaigning and turning out the vote in the state’s urban centers.

The temptation, however, is tempered by the fact that she currently represents one of the safest Democratic seats in the nation, where active Democratic voters outnumber Republicans by more than 2-to-1. Titus is congresswoman-for-life. But she’s also a relentless campaigner who’d benefit from liberal attacks on Heller over issues such as his votes for Donald Trump’s Cabinet nominees.

Other Democrats have different strengths and weaknesses.

Ford lacks the name recognition that is vital to mounting a statewide bid. (Thus far, he’s represented only a Las Vegas state Senate district.) His profile will increase this year, however, thanks to his stewardship of the upper house, and the degree to which he can actually build his “Nevada Blueprint.”

Kihuen now represents a wide swath of Nevada in the 4th Congressional District, but he’s been doing so only for about five minutes. He’s ambitious, however, and U.S. Senate seats don’t come along all that often (the next will be Cortez Masto’s in 2022, and she’s likely to run for re-election). It’s enough to tempt a fast-riser to give up a competitive House seat for the reward of having to run only once every six years.

Marshall has a base in Northern Nevada, where she might make inroads against Heller, and she has statewide name recognition thanks to her two terms as treasurer. (She ran for secretary of state in 2014, but was subsumed by the red tide.)

2018 is going to be a tough year for Democrats nationally; they have 25 Senate seats up for grabs. If a Democrat can manage to get by Heller, Nevada — as in 2016 — might be the party’s one bright spot on election night 2018.