McCormick and Oz are fighting over tiny batches of votes in county after county. That’s how tight the Pa. GOP Senate primary is.

Every vote matters.

With a razor-thin margin separating celebrity doctor Mehmet Oz and former hedge fund CEO David McCormick in the Republican Senate primary and a recount officially announced, their armies of lawyers have fanned out across Pennsylvania’s counties to fight over every last ballot.

In addition to litigation in state courts, the campaigns have been lobbying county boards of elections about undated mail ballots and challenging small pockets of votes.

That small-bore politicking demonstrates the ongoing strategies of the two candidates as the final votes are counted and the race heads toward the recount — every vote McCormick can add is an opportunity to close the gap, every vote Oz can get thrown out helps protect his margin.

But both sides are being even more tactical than that. Depending on the county and specific circumstances, they’re sometimes broadly contesting votes, sometimes targeting individual ballots with surgical precision, and other times abandoning challenges they’ve already filed.

The careful fight over every vote also helps cut through both campaigns’ confident rhetoric and reveals just how uncomfortably tight the numbers are: A more definitive election result would not require this level of fighting over fistfuls of votes in individual counties.

The campaigns’ very presence at so many county elections board meetings is unusual, and county officials said representatives for both Oz and McCormick have flooded them with requests for information.

“They’ve just called us 80 times a day, and it’s the same questions 100 times,” said Northumberland County elections director Nathan Savidge. “ ‘How many uncounted?’ … ‘How many provisionals?’ … And it’s just the fact that they have asked it literally 10, 15 times a day.”

» READ MORE: David McCormick, Mehmet Oz, and the politics behind undated Pennsylvania mail ballots

Both campaigns had asked about sending representatives to watch the county’s recount, he said; neither had sent anyone to watch the original counting of the ballots.

Fewer than 1,000 votes now separate Oz and McCormick, and there are perhaps only hundreds of votes for either left to count — depending in part on which side has more success in getting votes accepted or rejected. And those votes are scattered across the state, and in different categories of vanishingly tiny numbers.

In Philadelphia, the Oz campaign filed a general challenge to automatically contest all provisional ballots cast at the polls by Republicans whose mail ballots had been rejected for technical flaws.

There were only two such votes.

The McCormick campaign, meanwhile, painstakingly challenged individual provisional ballot after individual provisional ballot, ultimately opposing 64 of them (including the same two as the Oz campaign).

In Delaware County, a lawyer for the Oz campaign filed a challenge to get 12 provisional ballots counted that the county planned to reject, only to withdraw the request three days later.

On the other side of the state, the two campaigns filed challenges against 30 provisional ballots in Allegheny County. McCormick challenged 19, Oz challenged five — and the remaining six were challenged by both.

Elections officials have to review each challenge to determine how to respond: Is the voter alive? Is the voter registered at that address? Did the voter’s party change? Did the voter vote in some other way? Is there anything suggesting fraud?

That means each additional challenge adds time and work to the vote count. When Philadelphia officials voted on provisional ballots Friday and gave the campaigns a chance to justify why they had challenged them in the first place, the McCormick and Oz lawyers said nothing.

“To not offer testimony to back up a challenge that you made really makes me wonder if it’s worth the investment,” said city elections chief Lisa Deeley, a Democrat. “However, in the future, I would just ask that you consider the time and the burden that it’s putting on our staff to do these frivolous challenges.”

Seth Bluestein, the Republican on the board, expressed similar frustration.

“In the future it would be worth the candidates and parties looking at the frivolousness of what they are challenging before they make these challenges,” he said. Referring to the challenges that had just been resolved, he said: “As you can see, a lot of them are not really relevant.”

Much of the fight isn’t in such formal challenges to the legitimacy of specific ballots — the campaigns are attending county elections meetings to gather information on the count and push officials to adopt their view of which votes should count or not.

At a meeting Tuesday, a lawyer for Oz’s campaign urged Bucks County elections officials to hold off on counting provisional ballots until it could more closely review the circumstances behind each vote. The board, unmoved, proceeded with considering and counting the ballots that day.

And it’s not just provisional ballots.

» READ MORE: What you can expect in the recount in the Pa. Republican Senate primary

The campaigns have particularly sparred at the county level over undated mail ballots, which arrived on time but without the required handwritten date on the outer envelope.

Undated ballots are at the heart of ongoing legal battles in state and federal court, including a planned appeal to the U.S. Supreme Court after a federal appeals court last Friday said undated Lehigh County ballots from last year must be counted. Based on that ruling, the McCormick campaign, which has outpaced Oz in mail ballots, sued this week in state court to count all undated mail ballots in this election. (The Oz campaign and the state and national Republican Parties oppose that position.)

The Pennsylvania Department of State, which oversees elections, told counties to count undated ballots, but keep the tallies and physical ballots separate, pending further guidance from the courts.

The fight over undated mail ballots, while taking place statewide, is still over a minuscule number: There are only about 860 undated mail ballots, acting Secretary of State Leigh M. Chapman said at a news conference Wednesday.

That number was based on reports from 65 of 67 counties. Of the other two, Northumberland County had no undated Republican mail ballots, and Centre County had 19, with four votes for Oz, zero for McCormick, and 15 for other candidates.

» READ MORE: Fetterman got a defibrillator after his stroke. But doctors say the campaign’s story ‘doesn’t make sense.’

Other counties also reported very small numbers.

When Delaware County opened its undated mail ballots and counted them, there were two for Oz and three for McCormick.

That means those votes, if included in the final result, would shift the margin by one.

But in this election? For McCormick and Oz?

Every single one matters.