The most hotly anticipated event so far in the 2022 primary season will unfold today in Pennsylvania, where voters of both parties will make crucial decisions in competitive races for Senate and governor.

The results will help clarify the mood of the country: Pennsylvania, a longtime swing state, has often signaled what American voters are thinking.

And right now, a forceful centrifuge seems to be spinning Pennsylvanians further toward the partisan edges. The state once took pride in electing center-left or center-right politicians to its highest offices. But at least on the Republican side, that history counts for little right now.

The party’s high-octane primaries for governor and the Senate have grown increasingly turbulent in the final stretch. The leading candidates support ending abortion rights; some have amplified former President Donald J. Trump’s lies about a stolen 2020 election; and all seek to persuade voters of their MAGA bona fides.

North Carolina is also holding primaries that will decide the fate of Representative Madison Cawthorn, who has been plagued by scandals and made many enemies among fellow Republicans, as well as whether Mr. Trump’s support can lift a 26-year-old former football player and political novice in a House G.O.P. race.

Here’s what we’re watching for:

Can Trump again pull a struggling candidate over the finish line?

Polling shows the G.O.P. Senate primary in Pennsylvania in a statistical three-way tie between Dr. Mehmet Oz, the celebrity physician; David McCormick, a former hedge fund executive; and Kathy Barnette, a far-right commentator who has surged in the campaign’s final days thanks to a compelling biography and sharp debating.

At one debate, Dr. Oz, who has won Mr. Trump’s endorsement, plaintively asked, “Why is everyone attacking me?” Ms. Barnette shot back: “Because you’re a liberal.’’

The Republican race, with five major candidates, has been dominated by nearly $40 million in television ads spent by the two early front-runners, Mr. Oz and Mr. McCormick, and their allies. Most of their TV spots have been attacks bludgeoning one another.

Ms. Barnette, on only a shoestring budget, vaulted into contention by emphasizing her personal story — she revealed she born after her mother was raped at age 11, galvanizing anti-abortion voters — and by emerging as an alternative for Republicans unconvinced that Dr. Oz or Mr. McCormick were authentic conservatives.

The race will test the power of the Trump endorsement, even more than was the case in Ohio two weeks ago, where the former president pulled J.D. Vance, who had been polling in third place, over the finish line.

In Pennsylvania, Mr. Trump’s blessing of Dr. Oz met with major pushback pointing out that the doctor was a “Hollywood liberal” and friend of Oprah Winfrey’s. At a rally Mr. Trump held in Pennsylvania 11 days ago, boos greeted the mention of Mr. Oz’s name.

“MAGA does not belong to President Trump,” Ms. Barnette said at one debate. Today will tell.

Will Democrats choose an outsider for Pennsylvania governor?

The Democratic Senate primary in Pennsylvania has revealed that many Democratic voters, like their Republican counterparts, increasingly desire political brawlers and reject consensus-seeking centrists.

That’s why John Fetterman, the state’s iconoclastic 6-foot-8 lieutenant governor, has held a big polling lead for weeks. He has appealed to rank-and-file Democrats who want a progressive in office — as well as one they believe will appeal to working-class white voters. Over the weekend, he announced that he had had a stroke on Friday and was recovering.

Representative Conor Lamb, who won three races in districts thick with Trump supporters, has used that as a calling card to win the backing of many elected Democrats in the state, who believe he would be the most electable in November. That argument has not been embraced by rank-and-file Democrats, however.

A third candidate, Malcolm Kenyatta, a young left-leaning state lawmaker from Philadelphia, would be the first Black and openly gay nominee should he pull off an upset.

In the G.O.P. governor’s race, extremism is on the ballot.

Two big issues will overshadow Pennsylvania’s open race for governor in the fall: voting access and the future of abortion, should the Supreme Court overturn Roe v. Wade.

In the Democratic primary, Josh Shapiro, the state’s attorney general, is running unopposed. Mr. Shapiro won multiple lawsuits brought by Trump supporters falsely claiming fraud in the 2020 election. He has said he will campaign on voting rights and on protecting abortion access, which could turn the race into a referendum on the issue.

Should Roe be overturned and abortion become an issue decided state by state, Pennsylvania’s Republican-led legislature is expected to pass a bill with sharp restrictions. Mr. Shapiro has said he would veto it. The top four Republicans vying for the nomination all support abortion bans.

Doug Mastriano, the clear G.O.P. front-runner in polls, was a key figure in Mr. Trump’s effort to overturn the 2020 election results in Pennsylvania. He chartered buses to the Jan. 6 protests in Washington and has made false claims of election fraud a central plank of his bid to lead a state that will be central to the 2024 presidential race. Mr. Trump weighed in on Saturday with a late endorsement of Mr. Mastriano.

Fearing that a Mastriano victory would put an unelectable hard-right nominee on the ticket, some prominent Republicans have coalesced in a Stop Mastriano effort behind Lou Barletta, a former congressman who appears second in most polls.

The other chief contenders in the race are Bill McSwain, a former U.S. attorney, and Dave White, a businessman.

How will Madison Cawthorn fare in North Carolina?

In North Carolina, the Republican primary for Senate is the most prominent contest, though most eyes are likely to be elsewhere: on whether the explosively controversial Representative Madison Cawthorn, 26, will be renominated in his district in the state’s far west.

The number to keep in mind is 30: The top finisher in North Carolina primaries must gain a plurality of more than 30 percent of the vote or face a runoff against the second-place candidate.

Mr. Cawthorn, who has seven challengers, has been in the news for all the wrong reasons: for possessing a firearm in an airport (again), for driving with a revoked license (again) and for being rebuked by House Republican leaders for his comments suggesting that lawmakers had used cocaine and held orgies.

It is unclear, however, if these antics will allow any of his rivals, most likely State Senator Chuck Edwards, to force a runoff. Cawthorn is still a national MAGA celebrity with Mr. Trump’s endorsement.

In the Senate race, for an open seat, Representative Ted Budd, also endorsed by Mr. Trump, has made a late surge, seeming to surpass former Gov. Pat McCrory.

Mr. McCrory, whose conservative credentials include signing the infamous 2016 “bathroom bill” that targeted transgender people — and drew a major backlash upon his state — is no longer conservative enough for some Republicans. The anti-tax Club for Growth has brought millions of dollars in TV attack ads down on his head, accusing him of being “a liberal faker.”

The presumptive Democratic nominee is Cheri Beasley, a former chief justice of the North Carolina Supreme Court.

And don’t forget this House primary.

The power of Mr. Trump’s endorsement will also be tested in a G.O.P. primary for a new North Carolina congressional district, the 13th, which is south of Raleigh and is likely to be the state’s only competitive House seat in the fall.

The former president has thrown his weight behind a former college football player, Bo Hines, 26, who is also being backed by the Club for Growth’s political committee. His main opponent, Kelly Daughtry, is the daughter of a former majority leader of the statehouse. Many Republican officials in the state are pulling for Ms. Daughtry. Sound familiar?