The special election in Arizona’s 8th District will set the stage for a hotly contested Senate race and a handful of competitive House races in the Grand Canyon State. And both parties are watching for indications of what’s to come in November.

More than 150,000 people have already voted in the contest to replace Republican Rep. Trent Franks, who resigned in December amid allegations of sexual misconduct. Democrats are hopeful they can make the race close even though President Donald Trump carried the suburban Phoenix-based district by 21 points in 2016. And Republicans know analysts will be looking at the outcome for signs of a potential blue wave.

“They’re going to be watching and we have to win big,” GOP Rep. Martha McSally said while campaigning Saturday for the Republican nominee, former state Sen. Debbie Lesko, according to video posted by NBC News.

“She has got to crush this,” added McSally, who is running for Senate. 

Lesko faces former emergency room physician Hiral Tipirneni, who Democrats have lauded as an impressive candidate. Party operatives say her outsider status and focus on health care and protecting Social Security and Medicare have helped tighten the race.

“If Hiral wins, or if the race is even in single digits, and you’re a Republican anywhere else in the state, you’re probably on notice,” said DJ Quinlan, a former executive director of the Arizona Democratic Party who has been advising Tipirneni’s campaign.

Watch: What to Know in Arizona’s Upcoming Special Election

Another target?

Unique turnout dynamics and national attention can make special elections outliers, which is why some operatives caution not to draw too many conclusions from one contest.

But campaigns for both parties in the state’s Senate and other House races will be watching the results, particularly how independents vote. Democrats are looking at how many Republicans cross over to Tipirneni, while Republicans will be watching turnout among base voters.

Arizona is hosting three competitive House races this year, but Democrats contend there could be four. Multiple party operatives said that if Tuesday’s margin is within single digits, that could spell trouble for nearby GOP Rep. David Schweikert.

“It could be a surprising one,” said one national Democratic operative. Democrats say the demographics in the 6th District are more favorable than the 8th.

Trump carried the 6th District by 10 points with 52 percent of the vote, while Schweikert was re-elected to a fourth term with 62 percent. The GOP voter registration advantage is nearly identical to the 8th District, with 40 percent registered Republicans, 24 percent Democrats, and 34 percent not registered with a party. Inside Elections with Nathan L. Gonzales rates the race Solid Republican.

Democrats believe they can make inroads with higher-educated, suburban voters in the 6th. One national GOP operative said that while the district’s suburban nature could make it competitive, there wasn’t any evidence of that yet.

“They’ve tried to make that seat a thing,” the GOP operative said of Democrats. “They don’t have a candidate that they seem that excited about.”

Schweikert has more than five times the amount of cash on hand as his closest Democratic challenger, with $370,000 in the bank, according to Federal Election Commission documents.

Leading the 6th District Democratic contenders is Heather Ross, a nurse and professor, who had $72,000 on hand. Former journalist Anita Malik had $16,000, while lawyer Garrick Madden only had $55 in the bank after raising and spending $69,000. But one Democratic consultant said attention could quickly shift to the 6th District after Tuesday’s special election.

“It instantly elevates our race,” Ross’ campaign manager Jeanne Lunn also said. Lunn said the Ross campaign has been in contact with the DCCC.

Ross’ campaign suspended its field operations over the weekend so volunteers could focus on the 8th District special election. Both Ross and Lunn have been knocking on doors for Tipirneni.

Schweikert’s team did not respond to a request for comment, but he also hit the campaign trail for Lesko on Saturday, speaking at the same event as McSally.

The congressman suggested the special election was a way for Democrats and the “parasite class” to fundraise and build their contact lists to advance “radical politics,” according to video from NBC News.

“We need to crush them,” Schweikert said.

Other House contests

Former Democratic Rep. Ann Kirkpatrick is also closely watching the 8th District race, even though the Tucson-based 2nd District, where she’s seeking a comeback, is more than 100 miles away from the Phoenix area.

Kirkpatrick is running for the House seat McSally is vacating. Hillary Clinton carried the 2nd District by 5 points in 2016 and Inside Elections rates the race Tilts Democratic.

Kirkpatrick, who represented the 1st District for three terms before losing a bid for Senate in 2016, has sent out several fundraising emails, urging supporters to split donations between her and Tipirneni.

“Form the point of the Kirkpatrick campaign, we look at [the special election] and see that even in one of the most Republican districts, more and more voters are fed up with candidates who are hostile to affordable health care and to public education,” one Kirkpatrick adviser said.

Also watching the Lesko-Tipirneni race is physician and former state Rep. Matt Heinz, who is challenging Kirkpatrick for the 2nd District Democratic nod. His campaign manager Brian Robinson said in an email that Tipirneni emphasizing her health care experience “can serve as a template for some of the themes we’ll be rolling out.”

The top Republican in the 2nd District race, Tucson Hispanic Chamber of Commerce President Lea Marquez Peterson, is “casually observing” the special election, her consultant Stephen Puetz said. He said they won’t be drawing too many conclusions because the 8th District is in a different part of the state.

Puetz said Marquez Peterson’s background in business and her roots in the district make her a unique candidate, and one who would be independent of her party. (Democrats counter that she has been active in party politics — she was an adviser to Republican Gov. Doug Ducey and co-chaired Hispanic outreach for GOP Sen John McCain’s 2016 race.)

Democrats are also trying to hold onto the 1st and 9th districts, which Republicans eye as potential pickup opportunities in a difficult midterm cycle.

Democratic Rep. Tom O’Halleran succeeded Kirkpatrick in the 1st District, winning by 7 points in 2016. But Trump carried the seat by 1 point and national Republicans see lawyer and farmer Tiffany Shedd as a strong challenger to the freshman lawmaker.

In the 9th District, Democrats are confident of holding the seat being vacated by Rep. Kyrsten Sinema, who is running for Senate. Phoenix Mayor Greg Stanton is seeking the Democratic nod in a district Clinton carried by 16 points. But one Arizona Democratic consultant described physician and Navy veteran Steve Ferrara as a strong recruit for Republicans.

Democrats say a close margin in Tuesday’s special election could indicate they have a better chance at hanging on to those two seats and flipping the 2nd, all three of which are much less Republican than the 8th.

Senate race

The Senate campaigns also have eyes on the 8th District contest. Inside Elections rates the Senate race a Toss-up.

McSally is locked in a three-way primary for the GOP nomination with former state Sen. Kelli Ward and controversial former Maricopa County Sheriff Joe Arpaio. (The 8th District is located entirely within Maricopa County.)

McSally, with her base in Tucson, was campaigning with Lesko in an area of the state where she is looking to boost her name recognition. The 8th District is also home to reliable GOP voters — many of them seniors who consistently turn out, and could be crucial for Republicans running statewide.

Ward also showed her support for Lesko on Twitter, sharing a picture of the two at a “Bikers for Trump” rally Monday. Ward’s strategist Eric Beach said her volunteers in the area were also helping Lesko’s campaign, and he was not concerned over the implications of a close margin on the Senate race.

“There will be no panic from our end,” Beach said. “We feel that we are much in tune with the Arizona voters.”

Arpaio’s campaign did not respond to a request for comment. 

Democrats watching the Senate race say the 8th District result could show if they can make inroads in Republican areas. Likely nominee Sinema also represents a Phoenix-area district.

“Persuasion can happen anywhere and they shouldn’t ignore any part of the state,” one Arizona Democratic consultant said of Sinema’s campaign. “Part of the pathway to victory should be competing in every corner of the state.”

Tipirneni had a similar message when asked in a phone interview last week what her race could signal for November.

“We should be challenging every seat,” she said. “We know that conventional wisdom does not apply anymore.”