The Senate majority leader, Chuck Schumer, is not inviting the apparent senator-elect from Pennsylvania, Dave McCormick, to the Senate orientation, citing ballots that still need to be counted. Some Republicans say they are not content with sitting back and letting the apparent winner of the race be left out.

Mr. McCormick is projected to win the Pennsylvania race, unseating the incumbent Democratic senator, Bob Casey. The Associated Press called the race for Mr. McCormick on Thursday. However, a spokesman for Mr. Schumer explained the decision not to invite the likely senator-elect, saying, “With over 100,000 ballots left to be counted in Pennsylvania, the race has not been decided. As is custom, we will invite the winner once the votes are counted.”

While projections by news outlets about who will win an election are not the official results, Mr. Casey faces an uphill climb to retain his seat. The AP notes he handily won Philadelphia, but Mr. McCormick “sliced significantly” into his support. The Democrat senator’s share of the vote at Philadelphia dipped eight percentage points from six years ago. 

Mr. Casey has not conceded the race as of Monday morning. With roughly 98 percent of the expected vote counted, Mr. McCormick was leading by more than 40,000 votes. 

In response to Mr. Schumer’s decision, some Republicans suggested they would help the new senator-elect make it to the orientation. Senator Lee wrote on X, “I’m willing to personally escort [McCormick] into the Capitol for new-senator orientation. I’d like to see how they’d keep him out if he literally walked into ‘the room where it happens.’”

Senator Britt reacted to Mr. Lee’s post, writing, “I’ll be right there alongside you, Mike.”

Senator Schmitt of Missouri told Mr. Schumer to “stop being a baby & take the L.” He also shared several GIFs implying he would help escort Mr. McCormick into the Senate. 

Mr. Schumer’s decision to withhold the invitation to the Senate orientation has also drawn criticism from some senators, who did not go so far as to threaten to help usher Mr. McCormick into the chamber. 

Senator Sinema, who is retiring at the end of this year, posted on X, “In 2018 my race wasn’t called for 6 days. I jumped on a redeye to DC to make senate orientation-I learned so much & made lasting relationships that week. Dave McCormick & Ruben Gallego will be Senators for PA & AZ. They should be invited to orientation & start learning the job.”

The outgoing senator from West Virginia, Joe Manchin, also said Mr. McCormick won, writing on X, “While we are losing a good person and colleague in Senator Bob Casey, I believe the Senate will be gaining another good man in Senator-Elect David McCormick.”

Senator Romney said Mr. McCormick should “obviously be invited to attend freshman senator orientation.”

Senator Rubio asked, “What happened to all the demands that our leaders accept the outcome of the elections?”

Senator Scott of Florida, who is in the running for Senate majority leader, posted on X that “Dave McCormick is the senator-elect.” He called Mr. Schumer’s “move to not allow him to participate in orientation this week is disgusting. They did the same thing to me after I beat a Democrat in 2018. We have to fight this! AP called it. Dave won, Casey must concede NOW.”

Senator Cornyn and Senator Thune, who are running to lead the Republican conference, criticized Mr. Schumer as well. 

While Republicans already have enough seats for a majority in the upper chamber, increasing their margin could neutralize some of the more moderate voices in the conference. It would also give them a buffer to limit the chance of their work passing President Trump’s agenda, and confirming appointees would grind to a halt if members are sick or if they step down or die.