At one point, Democrats seemed poised to take a couple of Senate seats away from Republicans in a cycle where far more of their colleagues remain vulnerable. Observers had all but written off Dean Heller in Nevada, the only incumbent Republican in a state won by Hillary Clinton two years ago. Jeff Flake’s retirement in Arizona, a state that has edged toward Democrats over the last few years, appeared to give Democrats an opportunity to push it even harder to the left.

And then the Brett Kavanaugh hearings happened. Whether causative or merely correlative, the race in Arizona has turned sharply toward the GOP, according to a new poll from the local ABC affiliate:

A new poll of Arizona’s contested Senate race shows frontrunner Republican Martha McSally increasing her lead over Democrat Kyrsten Sinema.

In the latest ABC15/OH Predictive Insights poll, McSally has a six-point edge on Sinema, 47 percent to 41 percent. Eight percent said they had yet to decide on a candidate.

Both candidates received less support than they did in September when McSally held a 49-46 margin, the first time ABC15/OHPI polling showed her in the lead to replace retiring Sen. Jeff Flake.

The poll series tracking shows the abrupt change in fortunes for McSally and what looks like a collapse for Sinema:

It’s the first poll in a month showing a McSally lead; in fact, it’s the same polling series that showed her last lead, although a Gravis poll put her up by a point at the same time. Interestingly, the drop occurs even though Sinema is seen slightly more favorably (46/42) than McSally (37/45). They both hold 80% of their own party’s voters, but McSally is winning independents now by 12 points, 48/36. McSally even edges Sinema in Maricopa County 46/44, an impressive result if it holds up.

What about Nevada? According to a new NBC poll, the rumors of Dean Heller’s political death may have been at least slightly exaggerated:

Democrats and Republicans are running neck and neck in Nevada’s key contests for U.S. Senate and governor, according to a new NBC News/Marist poll of the state released Tuesday, four weeks before Election Day.

In the Senate race — one of the Democrats’ best pick-up opportunities in their bid to win control of that chamber — incumbent Republican Sen. Dean Heller gets support from 46 percent of likely voters, while Democratic challenger Jacky Rosen gets 44 percent.

When the matchup is expanded to include the Libertarian candidate and “none of these candidates,” which is an option on the Nevada ballot, Heller continues to lead by 2 points, 44 percent to 42 percent.

This result might be tougher to chalk up to a Kavanaugh effect, in part because the poll actually asked about Kavanaugh’s confirmation. Among likely voters, confirmation was opposed by a within-the-MoE 38/41. That’s not necessarily going to be decisive, but it also doesn’t indicate a groundswell of Republican enthusiasm based on the hearings either.

Heller’s not out of the woods by any means. Any incumbent below 50% this close to the midterms risks undecideds breaking to the challenger. Thirteen percent of likely voters describe themselves as still persuadable, a very high percentage this close to the election with an incumbent in place. A majority of likely voters are motivated by a desire to strengthen Democrats as a check on Donald Trump. The GOP leads the generic ballot question, but only by one point, 48/47, with a two-point plurality on control of Congress (47/45), both virtual ties.

Still, a month ago, analysts were writing Heller’s political obituary and practically measuring drapes for Sinema. This is the first poll giving Heller any lead at all since July, but he’s been hanging in around the margin of error all along. If the Kavanaugh effect is real, it may well foreclose on any pickup opportunities Democrats had in this cycle — and with it their hopes for snatching control of the Senate and of Donald Trump’s appointments in the second half of his term.