Republicans have just nine seats up for grabs this November, but in a Democratic year, the party’s few vulnerabilities could easily be exposed by the Democrats. The Republicans are defending just a single seat in Clinton territory — Nevada — but several other states are looking competitive six months from election day. Over the next few weeks, I will be previewing the various 2018 Senate races, beginning with the seats Republicans are defending. Today we arrive in Arizona.

Arizona (open seat) — Likely Democrat

Arizona has been a staunchly Republican state for decades, but 2018 is looking like a great opportunity for Democrats to take their first Senate pickup. Before last Tuesday, I would have considered this seat leaning D, but after the most recent special election results, I find a Democratic win here even more likely.

In a district that Republicans regularly win by 20 or more percentage points, Democrat Hiral Tipirneni came within nearly five points of winning last week. The Democratic candidate was not a particularly strong one, and Republican Debbie Lesko was not a particularly weak one. Yet, Democrats came close to an upset in this ruby-red district. Republicans made up 48 percent of the electorate, meaning that the Tipirneni not only swept up the independent vote but also won a sizable number of Republican voters. With a median age at nearly 70-years-old in last week’s election, November’s electorate will be far younger and more susceptible to vote for the Democrat.

The likely Democratic candidate is Kyrsten Sinema, who currently sits in the US House as the representative from Arizona’s 9th Congressional District. Sinema is an interesting politician. A former member of the Green Party, Sinema accrued an incredibly progressive voting record in the Arizona legislature. Once elected to federal office, however, Sinema moderated considerably. Sinema is now considered one of the most moderate members of the House. She has voted with Trump 57 percent of the time, according to . Sinema’s moderate record may not be loved by liberals, but her profile is a good fit for a purple state like Arizona. The likely Democratic candidate is Kyrsten Sinema, who currently sits in the US House as the representative from Arizona’s 9th Congressional District. Sinema is an interesting politician. A former member of the Green Party, Sinema accrued an incredibly progressive voting record in the Arizona legislature. Once elected to federal office, however, Sinema moderated considerably. Sinema is now considered one of the most moderate members of the House. She has voted with Trump 57 percent of the time, according to 538 . Sinema’s moderate record may not be loved by liberals, but her profile is a good fit for a purple state like Arizona.

The Republican field is far more competitive, but polling shows that Democrats could get very lucky with who emerges from the GOP primary. Conspiracy theorist and far-right state senator Kelli Ward is running for the nomination. The candidate is considered to be such a poor one that the Republican party has run ads against the candidate with the nickname “Chem-trail Kelli” because of her alleged promotion of chem-trail conspiracy theories. Polling conducted so far this year shoes Sinema with an average of a 9-point lead against Ward.

Another candidate, Joe Arpaio, would essentially turn over the race to Democrats if he emerged from the primary. The former-sheriff is known throughout the country as an oppressive sheriff who treated his detainees in near “ concentration camp ” conditions. He was also pardoned by President Trump when convicted on charges related to the treatment of prisoners. While Trump was winning Maricopa county, the home of Phoenix, by 3 percentage points, Arpaio lost the county by 11 percentage points. Polling between Arpaio and Sinema so far this year shows the Democrat leading the race by 27.5 percentage points. Arpaio’s nomination would gift the race to Sinema.

The strongest Republican candidate is Martha McSally, the current representative for Arizona’s 2nd district. The candidate is considered a right-wing hardliner, but compared to the other candidates in the race is the most “moderate.” Even so, McSally is losing to Sinema by an average of 7 percentage points in polling so far this year. That’s a dire proposition for the “most-electable” Republican to find herself in.

So far, the average of polling shows the Republican side wide-open. Any of the candidates at the current moment could foreseeably emerge from the primary, putting the GOP in a precarious position.

The money race doesn’t show a much better picture for the GOP. At the end of March, Sinema had $6.7 million cash on hand. She raised $2.5 million in a single quarter. That is a crazy haul for a Democrat running in a “Red” state.

On the Republican side, McSally had $3.2 million cash on hand, less than half what Sinema had. Kelli Ward had $400,000 on hand, while Arpaio had $250,000.

The Republicans will likely burn through most of their cash in the competitive primary, while Sinema will be able to continue to fundraise with limited competition from other candidates. By the time the primary finishes up, we could see a potentially insurmountable monetary lead for the Democrat.

There’s one other wildcard that could become a factor in the race. Republican John McCain could potentially leave his Senate seat before May 30, triggering a special election this November. If this occurs, a second open seat would open up, which would likely encourage either Kelli Ward or Joe Arpaio to switch races. The two candidates feed off a similar type of voters and they are in direct competition with each other for GOP hardliners.

If a second Arizona vacancy opened up and Arpaio moved to the open senate race, it would likely ensure Ward would win the nomination in the regular senate seat. That would rob Arizona of their best candidate for the seat, likely gifting the seat to Democrats.

Other raters have this senate race in the “tossup” category, but I’m not convinced the Republicans have a good shot to keep this seat. Special election results don’t look too kind, while the current candidates don’t make GOP prospects much better. Polling doesn’t show a close race either. There are far more things that could go wrong for Republicans in Arizona, while Democrats have far more things that could go right for them. For now, this seat is rated Likely Democrat.