In these discussions, Mr. Portman, who was President George W. Bush’s budget manager, helped fuel the political discussions for the Republicans, while Ms. Sinema messed up the group’s meetings and helped focus on the issues at hand.
“They have a good relationship and a relationship built on trust,” said Senator Susan Collins, Republican of Maine, in an interview about the couple.
To finalize the deal, the senators eventually split into small working groups, each tasked with drafting various aspects of the bill, including transit and broadband projects, and funding provisions.
During her birthday dinner last Saturday night, Ms. Sinema phoned Senators Jeanne Shaheen, Democrat of New Hampshire, Lisa Murkowski, Republican of Alaska, and Ms. Collins to reconcile a series of accounting numbers on unspent pandemic aid funds. an important funding mechanism, Ms. Collins recalled. (After calling the four senators “the wonder women,” Ms. Sinema presented the other three stemless wine glasses with the superhero’s logo.)
Mr. Portman spent nine hours Tuesday in his conference room in the Russell Senate Office Building with White House adviser Steve Ricchetti wrestling with remaining issues including financing transit.
At one point, Mr. Portman’s phone was so clogged with voicemails that Mr. Biden couldn’t leave him a message, according to a Republican official who was about to speak. (They connected later.)
“I really appreciated the constant communication between the two of them,” said Pete Buttigieg, the Secretary of Transportation, of Mr. Portman and Ms. Sinema during the negotiations.