In Iowa, Sen. Joni Ernst (R) has challenged her Democratic competitor to six debates, starting in August. In North Carolina, Sen. Thom Tillis (R) pressed his Democratic opponent to accept five debates, which he wanted to start in the spring.

And in Maine, Sen. Susan Collins (R) declared that she wants to debate her opponent 16 times, once in each of the state’s counties, starting immediately.

Republicans acknowledge that this upends the usual debate about debates, in which an incumbent rarely wants to give the challenger the same platform. Incumbent senators are pleading with their lesser-known rivals to join them on debate stages, or Zoom, trying to elevate the profile of these Democrats.

But they view this as a matter of necessity in a campaign in which Republicans are running into the head winds of President Trump’s sagging poll numbers amid his stumbling response to the coronavirus pandemic.

And the pandemic has limited campaign activities that are normal for a big Senate race, activities such as state fairs, beach walks and large church services — and without those staples, there are fewer chances for candidates to make mistakes.

Instead, Republicans are growing fearful that Democratic candidates are receiving such little scrutiny that they could steamroll to victory, and to the Senate majority, mostly by raising huge amounts of money that fund smart media campaigns on TV and social media.

“The more voters see their candidates, the worse off they are. This is a very weak crop of recruits,” said Jesse Hunt, spokesman for the National Republican Senatorial Committee.

Democrats contend that their candidates are doing as much as anyone could expect with the novel coronavirus still raging in many states, suggesting that the Republican senatorial nominee in Alabama, Tommy Tuberville, is the most shut-in candidate in the nation. Tuberville refused to debate former attorney general Jeff Sessions in the primary and has yet to agree to debate Sen. Doug Jones (D) in the general election campaign in a state that Trump won by nearly 30 percentage points.

Instead, Democrats say their candidates are focused on the right issue at the right moment — protecting and enhancing health care during a pandemic — as GOP incumbents adopt the tactics traditionally deployed by losing candidates.

“Democrats continue to meet with and hear from voters across their states, and they didn’t need a manufactured debate over debates from desperate incumbents to do it,” said Lauren Passalacqua, spokeswoman for the Democratic Senatorial Campaign Committee.

This Democratic crop largely comes from two sets of traditional candidates favored by Senate Minority Leader Charles E. Schumer (D-N.Y.): older former governors or ex-senators who already have high name recognition and fundraising history and lesser-known state officials who will execute their campaigns along the lines of DSCC mandates.

That recipe backfired in 2016, when former senators Russell Feingold (D-Wis.) and Evan Bayh (D-Ind.), along with former governor Ted Strickland (D-Ohio), lost races after being hailed as strong candidates.

Three former state officials — Patty Judge (Iowa), Katie McGinty (Pa.) and Deborah Ross (N.C.) — also lost that year.

Those Democratic candidates ran races closely aligned with the themes of Hillary Clinton’s campaign, believing she would thump Trump, and their results closely tracked Clinton’s. Feingold and McGinty were less than three-tenths of a percentage point from matching Clinton’s razor-thin losing margin in Wisconsin and Pennsylvania.

Now, Republicans think Democrats are taking a similar approach. Gov. Steve Bullock (D-Mont.) and former governor John Hickenlooper (D-Colo.) are the familiar faces. Republicans allege that state House Speaker Sara Gideon (D-Maine), former state senator Cal Cunningham (D-N.C.), along with former congressional candidate Theresa Greenfield (D-Iowa), are running races closely in line with DSCC marching orders.

Except, with Biden holding a larger lead than Clinton ever did, these Democratic candidates could have more success than their 2016 counterparts. On Thursday, the Cook Political Report, an independent analysis site, declared that Democrats were favored to get a net gain of four seats to claim the Senate majority in November (three seats if Biden wins).

Cunningham and Gideon are raising eye-popping amounts of money for their campaigns. Cunningham, a Bronze Star recipient from tours in Iraq and Afghanistan, has raised more than $15 million in his challenge to Tillis, while Gideon has raised more than $24 million.

Neither has even run a statewide race before.

Republicans think that if they can get on a debate stage with these nominees, they can make them look foolish.

“We’ve invited him — how many times does an incumbent invite a challenger to debates? He’s deferred on all,” Tillis complained in a recent interview with the conservative outlet Newsmax.

Tillis’s campaign has created a logo accusing Cunningham of campaigning from the “DSCC windowless basement.”

Cunningham and Tillis agreed Friday to two debates and are trying to schedule a third, not quite the five the incumbent wanted.

Democrats say Cunningham has held 11 events, either in person or over videoconferences, including eight town halls, in the past week. Gideon conducted six events, including talking with lobstermen and holding a roundtable on opioid abuse, since winning the Democratic nomination July 14.

And Greenfield has held four news conferences with Iowa media outlets in the past month, with goals including defending the Affordable Care Act and criticizing business-friendly rulings by the Environmental Protection Agency.

Part of the GOP frustration comes from the steadily shrinking ranks of local media outlets covering congressional elections — a trend that has only worsened with the collapse of ad revenue in the pandemic, leading to further newsroom layoffs.

That phenomenon gets combined with a national news corps that is heavily focused on covering coronavirus stories, limiting the number of stories from key Senate battlegrounds. GOP strategists feel that their incumbents still have to face the Capitol press corps every day that the Senate is in session, while the Democratic challengers carefully choose their public appearances.

This election season has not yet had a single big “tracker” controversy — involving those usually young staffers who follow opposing candidates from event to event, hoping to capture them on camera doing or saying something controversial.

With their ammunition limited, Republicans keep fighting over debates, nowhere as fiercely as in Maine.

Within hours of winning her nomination, Gideon made the first offer: five debates. Collins demanded 16 and accused her Democratic rival of hiding from voters. “I look forward to an open and accessible discussion with you about the future of our state and nation,” Collins wrote to Gideon.

Gideon told reporters that Collins was the one in hiding.

“We have traveled around Maine for the past 13 months. We have heard over and over again from people who have said they have not seen Senator Collins in a forum where they are able to ask her questions,” Gideon said.