(CNN)President Joe Biden's decades on Capitol Hill were on full display in his latest exasperated exchange with a reporter over congressional negotiations on Friday.
This is Biden's exchange with a reporter about his agenda's progress in Congress during a press conference at the White House. Thanks to CNN's Nikki Carvajal for transcribing:
President Biden wouldn't say if he was confident in his agenda making it through Congress, instead asking, "who wants to put money on anything that Congress is going to do?"
"Come on, guys," Biden responded to a reporter who asked if he was "confident" in Congress enacting his plans. "Have you ever been confident about anything with guarantee?"
"Look, folks, this is a process. This is a process," he said, smiling slightly and leaning over his podium. "I love you guys. But this is a process. And I don't know what you want me so say, 'yes, I'm absolutely certain?'"
He continued: "All I know what to do, and I really mean this, is to [do] my best to lay out what I think the country has to do and be as persuasive as I can."
"Thus far it seems to be working a little bit," he said.
To be clear: Biden is walking a fine line here, balancing optimism with pressure and expectation-setting with realism. While Biden is only on the fifth month of his presidency, with 36 years in the Senate and eight as vice president, he is well acquainted with how things work in Washington.
He reminded reporters as much last week, when asked if he could guarantee whether he had the votes for a bipartisan infrastructure package: "I don't have any guarantee. But what I do have is a pretty good read over the years of how the Congress and the Senate works," Biden said.
At the same Friday press conference, Biden bristled when questioned about the state of Afghanistan, where a formal withdrawal is nearly complete, and a major US air base was officially handed over even as US generals warn of a looming civil war.
"I want to talk about happy things," Biden said as a reporter asked a third question about the winding-down of America's longest war.
"I'm not going to answer any more questions about Afghanistan," Biden said later after detailing his drawdown plans, his hopes for the embattled civilian Afghan government and his view of US air support.
"I'm concerned that you guys are asking me questions that I'll answer next week. This is a holiday weekend, I'm going to celebrate it," Biden said.
White House press secretary Jen Psaki later followed up, saying Biden's shortness "wasn't related to Afghanistan" and that Biden was "was ready to be done answering questions."
The Point: Biden is tight-lipped on negotiating with Congress because after decades of experience, he knows just how unpredictable it can be.