President Joe Biden used his highly anticipated news conference Thursday to deliver a forceful defense of his foreign and domestic policies, and batted away questions about his ability to serve another four years even as he flubbed a reference to Donald Trump in one of his first answers.

“I’m not in this for my legacy. I’m in this to complete the job I started,” Biden said as he insisted his support among the electorate was strong and he would stay in the race and would win.

Fumbles notwithstanding, the president pushed back at every suggestion that was slowing down or showing noticeable signs of decline, or that he was not in command of the job. But he was facing a growing chorus of calls from lawmakers, celebrities and other prominent Democrats to step aside from the 2024 race.

“My schedule has been full bore,” he declared. “So if I slow down and I cant get the job done, that’s a sign that I shouldn’t be doing it. But there’s no indication of that yet - none.”

Democrats are facing an intractable problem. Top donors, supporters and key lawmakers are doubtful of Biden’s abilities to carry on his reelection bid after his disastrous June 27 debate performance, but the hard-fighting 81-year-old president refuses to give up as he prepares to take on Trump in a rematch.

The first questioner of Biden’s press conference asked about him losing support among many of his fellow Democrats and unionists, and asked about Vice President Kamala Harris. Biden was at first defiant, saying the “UAW endorsed me, but go ahead,” meaning the United Auto Workers. But then he mixed up Harris and Trump, saying, “I wouldn’t have picked Vice President Trump to be Vice President if she wasn’t qualified."

As of Thursday evening, a dozen House Democrats had called for him to exit the race. The press conference was an effort to show he's up for another four years; voters are watching and elected officials are deciding whether to press for another choice.

Trump weighed in live on Biden’s news conference with a post on his social media network of a video clip of the president saying “Vice President Trump.”

Trump added sarcastically, “Great job, Joe!”

Earlier, Biden's campaign laid out what it sees as its path to keeping the White House in a new memo, saying that winning the “blue wall” states of Wisconsin, Pennsylvania and Michigan is the “clearest pathway” to victory. And it declared no other Democrat would do better against Trump.

“There is also no indication that anyone else would outperform the president vs. Trump,” said the memo from campaign chair Jen O’Malley Dillon and campaign manager Julie Chavez Rodriguez that was obtained by The Associated Press.

The memo sought to brush back “hypothetical polling of alternative nominees ” as unreliable and it said such surveys “do not take into account the negative media environment that any Democratic nominee will encounter.”

Meanwhile, the campaign has been quietly surveying voters on Vice President Kamala Harris to determine how she’s viewed among the electorate, according to two people with knowledge of the campaign who spoke to The Associated Press on condition of anonymity to talk about internal matters.

The people said the polling was not necessarily to show that she could be the nominee in Biden’s place, but rather to better understand how she’s viewed. The research came after Trump stepped up his attacks against Harris following the debate, according to another person familiar with the effort. The survey was first reported by The New York Times.

“I think I’m the best qualified person to do the job,” he said Thursday.

While Biden has expressed confidence in his chances, his campaign on Thursday acknowledged he is behind, and a growing number of the president’s aides in the White House and the campaign privately harbor doubts that he can turn things around.

But they’re taking their cues from Biden, expressing that he is in 100% unless and until he isn’t, and there appears to be no organized internal effort to persuade the president to step aside. His allies were well aware heading into the week there would be more calls for him to step down, and they were prepared for it.

But in announcing a compact that would bring together NATO countries to support Ukraine, Biden referred to the nation’s leader Volodymyr Zelenskyy as “President Putin” to audible gasps in the room. He quickly returned to the microphone: “President Putin - he’s going to beat President Putin ... President Zelenskyy,” Biden said.

Then he said: “I’m so focused on beating Putin,” in an effort to explain the gaffe.

“I’m better” Zelenskyy replied. “You’re a hell of a lot better,” Biden said back.

Senate Majority Leader Chuck Schumer invited Biden’s team to meet with senators privately at the lunch hour to discuss concerns and the path forward, but some senators groused they would prefer to hear from the president himself. In the Senate, only Peter Welch of Vermont has so far called for Biden to step out of the race.

The 90-minute conversation with the president's team, which one person said included no new data, polling or game plan on how Biden would beat Trump, did not appear to change senators' minds. The person was granted anonymity to discuss the closed door session.

The meeting was frank, angry at times and also somewhat painful, since many in the room know and love Biden, said one senator who requested anonymity to discuss the private briefing. Senators confronted the advisers over Biden’s performance at the debate and the effect on Senate races this year

One Democrat, Sen. Chris Murphy of Connecticut, said afterward, “My belief is that the president can win, but he’s got to be able to go out and answer voters' concerns. He’s got to be able to talk to voters directly over the next few day."

At the same time, influential senators are standing strongly with Biden, leaving the party at an impasse.

Sen. Bernie Sanders, the Vermont independent, told AP he thinks Biden "is going to win this election. I think he has a chance to win it big.”

Sanders said he has been publicly critical of the campaign, and said Biden needs to talk more about the future and his plans for the country. “As we come closer to Election Day, the choices are very clear," he said.