Announcing advertising cutbacks in four battleground states and a big ad buy in Ohio signals that the GOP is playing defense as it attempts to reclaim the Senate — and that the party knows something about certain election races that the public polling doesn’t show.

The Senate Leadership Fund disclosed it would be putting $28 million into supporting the Republican nominee in Ohio, venture capitalist J.D. Vance, in his bid for the Senate. The move came after the GOP earlier this week announced multimillion-dollar cuts in ad buys in four battleground states: Arizona, Wisconsin, Nevada, and Pennsylvania.

A professor of political science at University of Georgia, Charles Bullock, argues that this is the Republicans moving to reallocate funding to races where they think it can make the most difference. He says the Republicans are shifting strategies in an effort to “hold the Democrats to just a 50-50” Senate, as the Democrats appear to be pulling ahead in some key races.

A survey of the polls shows that Ohio might be the GOP’s best chance to protect against Democratic gains in the upper chamber. Emerson College polling from August 16 shows Mr. Vance leading his opponent Congressman Tim Ryan by three points, though the average of polls still has Mr. Ryan leading.

The race is to replace Senator Portman, who is retiring this year, meaning that the GOP has just announced that it is putting nearly $30 million into protecting one of its own seats, in a year that’s been expected to produce a “red wave.”

The shuffling of ad money looks, at least in the Senate, like a defensive pivot going into November. Minority Leader McConnell as much as confirmed this in conversation with NBC on Thursday. “I think there’s probably a greater likelihood the House flips than the Senate,” he said. “Senate races are just different. They’re statewide, candidate quality has a lot to do with the outcome.”

This focus on candidate quality, or lack thereof, has been the story of the Senate in 2022, at least according to Mr. Bullock. He argues that President Trump has propelled weak candidates into Senate nominations.

“If Republicans fail to take the Senate they can all blame Donald Trump for it which would mean that he cost them the Senate in two consecutive elections,” he tells the Sun. “He’s picking losers — that’s the problem in Pennsylvania and Georgia, maybe Ohio and Wisconsin.”

As further evidence, he points to Mr. Trump’s $100 million Save America PAC, which has yet to dole out even $500,000 to his picks for Congress.

“If you’re a Republican and you’re hoping that Trump’s going to write you a big check, you might as well hope that Santa Claus is going to bring it to you,” Mr. Bullock says.

An associate editor at Sabato’s Crystal Ball, John Coleman, largely agrees that Mr. Trump has propelled weak candidates to nominations in 2022, but he has a different read on the GOP’s latest financial moves.

He argues that the Republicans are maneuvering to correct a mistake that they had been making so far this season, spreading themselves too thin going after blue states like Washinton. He argues that they are looking to consolidate a position in Ohio in an effort to prevent Democrats from running up the score in what should be a safe state.

“Maybe their thinking is that they can just lock down Ohio then at the end they can give a boost to Herschel Walker or Dr. Oz,” he says, adding: “There have definitely been rumblings that the NRSC isn’t super confident in Oz.”

This is to say that the Republicans might be looking to spend their funds in the final few weeks before the election, in an effort to keep the Democrats to only 50 seats in the Senate.

The problem here, he says, is that election season starts early, with mail-in and absentee ballots being cast weeks before November 8. Still, he argues, the move to spend in Ohio demonstrates Republican confidence in North Carolina and Wisconsin.

While both states have made headlines in recent weeks for public polls that show Democrats outperforming expectations, the move to spend big in Ohio suggests that Republicans are confident in their nominees in those states.

For his part, Mr. Coleman argues that Republicans will remain the favorites in Wisconsin and North Carolina unless the Democrats can post some consistent polling leads over the next few months.