While Sen. Joe Manchin, D-W.Va., is widely regarded as the public face of moderate Democrat opposition to the Senate’s $3.5 trillion budget reconciliation bill, Sen. Kyrsten Sinema, D-Ariz., was quietly given equal time of White House lobbying.

President Joe Biden met separately with Manchin and Sinema on Wednesday. The latter has been less notable in the opposition because she is not doing the public and televised appearances Manchin has done, The Washington Post reported.

“Today’s meeting was productive, and Kyrsten is continuing to work in good faith with her colleagues and President Biden as this legislation develops,” spokesman John LaBombard said in a statement Wednesday.

“Proceedings in the U.S. House will have no impact on Kyrsten’s views about what is best for our country,” according to LaBombard.

Notably, Sinema, 45, was one of the key Democrat architects of the $1.2 trillion infrastructure bill that passed the Senate earlier this summer with some Republican support, so she might have more to stand strong against in potential deals cut with the other side of the aisle.

Among those is to make sure items negotiated out of the infrastructure bill do not wind up in the $3.5 trillion budget package, sources told the Post.

Also, the tax increases that advanced through the Democrat-controlled House Ways and Means Committee might be a sticking point, according to a Republican senator who asked to remain anonymous.

“She does not like tax increases,” the GOP senator who worked with Sinema on infrastructure told the Post.

“I just don’t think they’re related in her mind, or in reality, and I think that’s what’s hard for people to understand. This is not all about trade-offs and hostage-taking. It’s just, each on its own merits.”

Republicans have come to Sinema’s defense amid pressure from Democrats to bend on her disinterest in the total $3.5 trillion price tag of the budget.

“I pray for Manchin and Sinema every night, give them a lot of love, wish them well, and hope they can withstand the pressure,” Senate Minority Leader Mitch McConnell, R-Ky., said in Kentucky over the recess. “I think they know this is the wrong thing to do for the country.”

Still, Sinema has more loyalty to Democrats than her infrastructure dealings with Republicans.

“I do believe that she just has a genuine concern with potential for overreach and negative fiscal repercussions,” Sen. Thom Tillis, R-N.C., told the Post.

Sen. Mitt Romney, R-Utah, warned Democrats and Republicans that they are going to find out how resolute she is.

“Anyone who thinks she’s going to be a pushover, is going to be severely surprised,” Romney told the Post.

Still, the lobbying comes from the highest level of the Democratic Party.

“The president had productive individual meetings with Sen. Sinema and Sen. Manchin about his Build Back Better agenda,” a White House official told the Post after Wednesday’s meeting. “He is in regular touch with a wide range of House and Senate members and continues to engage with them as we move forward on the reconciliation package so we can deliver for middle-class families.”

Meanwhile, Democrats in Congress say Sinema is earnest in her concerns.

“She’s gone through the whole package and has very specific concerns and questions about very specific pieces,” Sen. Christopher Coons, D-Del., told the Post, pointing specifically to his wishes for a multibillion-dollar Civilian Climate Corps in the bill.

“It’s a perfectly reasonable question. I spoke up in caucus and said, ‘you know, this is one of the ones I’m working really hard on.’ And she said, ‘O.K., I need answers to this, this, this, and this.'”

Sen. Richard Durbin, D-Ill., is No. 2 in the Senate to Majority Leader Chuck Schumer and the lead vote-counter.

“The conversations are ongoing to allay her concerns,” Durbin told the Post. “We take them very seriously, respect her positions, and try our best to find common ground.”

Sinema first came out after her work on the companion $1.2 trillion infrastructure bill brought passage in the Senate, noting that bill should not be piggybacked on the $3.5 trillion Senate budget reconciliation spending.

“While I will support beginning this process, I do not support a bill that costs $3.5 trillion,” she said in a statement this summer.

Still, Senate Budget Committee Chairman Bernie Sanders, I-Vt., the leader of the panel that constructed the plan, was talking only about one senator sinking it – not Sinema.

“Is it appropriate for one person to destroy two pieces of legislation?” Sanders told ABC News’ “This Week” on Sunday, responding to a Manchin question. “I think we’re going to work it out, but it would really be a terrible, terrible shame for the American people if both bills went down. And that is a real danger.”