Representative Steve Scalise of Louisiana, the majority leader, returned to the Capitol on Tuesday following a six-week absence during which he received a stem-cell transplant as part of his treatment for blood cancer.
His Republican colleagues in the House were counting on his return to impeach Alejandro N. Mayorkas, the homeland security secretary, after a humiliating setback last week, when three Republicans joined all Democrats in rejecting the charges, leaving the G.O.P. just one vote short of a majority.
“I am back,” a smiling Mr. Scalise, mask in his hand, told a Fox News reporter as he re-entered the Capitol Tuesday afternoon. Mr. Scalise said he was feeling “great” and expressed confidence that the impeachment vote would move ahead as planned.
“To be back in person is really exciting,” he said. “I’ve heard the votes are tight; every vote is going to matter around here.”
On Tuesday night, he wore a heavy-duty mask as he milled around the House floor during votes, greeting colleagues with fist bumps and hugs.
Last week, after the stunning defeat of the first impeachment attempt, Republican leaders quickly said they would try again as soon as Mr. Scalise could return, potentially even the next day. That raised questions about whether the majority leader might place his health in grave danger to help Republicans press their charges against Mr. Mayorkas, which cleared the House on Tuesday evening but are all but certain to die in the Democratic-led Senate.
But Mr. Scalise said on Tuesday that after being in isolation for weeks as he received an autologous stem-cell transplant, he had been cleared by his doctors to travel.
During the process, he said, “they basically give you no immunity system. Your system is really not able to fight off any diseases.” But Mr. Scalise said his doctors told him his white blood cell count was high enough that he could be cleared to “go back to being around people.” Mr. Scalise said he planned to resume his full in-person schedule.
On Tuesday, he stuck with his annual tradition of delivering king cakes to his colleagues and Capitol Police officers to celebrate Mardi Gras.
Mr. Scalise’s office said in a statement last week that he was in complete remission.
Mr. Scalise, the No. 2 Republican in the House, announced in August that he had been diagnosed with a rare form of blood cancer. He continued to work as he underwent treatment, including an aggressive form of chemotherapy.
House Republicans eager to move forward with the impeachment of Mr. Mayorkas on Tuesday cheered his return.
Representative Marjorie Taylor Greene, Republican of Georgia who has led the charge against Mr. Mayorkas, said on social media that Mr. Scalise had “put cancer in remission” and that the Louisiana lawmaker was notably returning on Fat Tuesday to #impeachmayorkas. During the October race for Speaker, Ms. Greene had raised concerns about Mr. Scalise’s diagnosis in opposing his bid for the gavel. On the House floor Tuesday night, she greeted him with a warm hug.
His allies in Congress said Mr. Scalise looked and sounded great and that they trusted he was not putting his health in harm’s way by rushing back to Capitol Hill because his party so desperately needed his vote.
“While Steve Scalise will always put his country before his own health issues, I trust him to make his own decisions and he doesn’t owe any of us an explanation,” said Representative Lance Gooden, Republican of Texas. “We are thrilled he’s back.”
Representative Ann Wagner, Republican of Missouri, said that she had been talking and texting with Mr. Scalise throughout his medical ordeal and that he was healthy enough that he planned to begin traveling again this weekend to campaign with fellow lawmakers.
“He’s in such great shape he’s going on the road on Friday when we get out, and helping members,” she said.
