PHOENIX - Arizona has two Democratic U.S. senators for the first time since the 1950s, but their hold on the swing-state seats could be tenuous, according to recent polling.

Sen. Mark Kelly, who is up for reelection next year, and Sen. Kyrsten Sinema, who doesn’t have to run again until 2024, each are viewed more unfavorably than favorably by likely Arizona voters, according to findings by OH Predictive Insights.

"Both Sinema and Kelly have work to do if they want to hold onto their seats," Mike Noble, the Phoenix-based firms chief of research said in a press release.

"For Sinema, she must rebuild some of the bridges she seems to have burned with voters in her own party. For Kelly, he will likely have to navigate a midterm environment with an unpopular Democratic president."

The findings reported Monday by OH Predictive Insights were based on an opt-in panel survey conducted Nov. 1-8, with a margin of error of 3.7%.

The results showed Kelly was viewed favorably by 41% of Arizona voters and unfavorably by 48%. President Joe Biden had similar numbers, at 43% favorable and 54% unfavorable.

“As President Biden faces his lowest approval ratings since taking office, voters are turning their frustration to Democratic candidates," Noble said.

"That's something Sen. Kelly should keep in mind as he faces reelection in one of the country's closest swing states.”

Sinema was doing better with the state's general electorate than Kelly or Biden, with 45% unfavorable and 42% favorable, but she's in danger of failing to get her party's nomination.

Nearly three-quarters of Democrats said they'd prefer a Democrat other than Sinema to be senator. Only 26% of Democrats wanted to see Sinema reelected. That wasn't much different than the 21% of Republicans who preferred her.

In Democratic polling of hypothetical head-to-head primary matchups, U.S. Reps. Ruben Gallego and Greg Stanton and Arizona Superintendent of Public Instruction Kathy Hoffman each beat Sinema by at least 20 percentage points.

"Sinema's holding out on the reconciliation bill caused a lot of political pressure from the left wing of her party, and her numbers were beginning to sour because of it," Noble said.

A bright spot for Democrats, however, is that 62% of all voters said they'd prefer Sinema or some other Democrat over a Republican.