• President Biden announced new commitments to help Ukraine bolster its air defense against Russia in his speech commemorating NATO's 75th anniversary.
• The aid comes over two years into Russia's brutal invasion of Ukraine.
• Along with the high-stakes Ukraine aid negotiations, this week's NATO summit is an opportunity for Biden to assuage Democratic fears about his 2024 candidacy, after his disastrous debate performance against Donald Trump.

President Joe Biden announced new commitments to help Ukraine bolster its air defense against Russia in a speech Tuesday commemorating NATO's 75th anniversary.

"Putin wants nothing less — nothing less — than Ukraine's total subjugation, to end Ukraine's democracy," Biden said. "We know Putin won't stop at Ukraine. But make no mistake: Ukraine can and will stop Putin, especially with our full collective support."

The aid will include new batteries and components for Patriot missile systems, donated by the U.S., Germany, Romania, the Netherlands and other partners. Italy will donate an additional SAMP-T missile system.

Speaking from a teleprompter, Biden said that more air defense supplies will be distributed to Ukraine in the coming months.

The announcement comes over two years into brutal invasion of Ukraine led by Russian President Vladimir Putin, a war that has become a point of contention on Capitol Hill as lawmakers remain divided on whether to keep providing funds for Ukraine's defense.

Biden's speech also served as the latest example of the split screen looming over the 2024 NATO summit this week: As the president holds high-stakes meetings with foreign allies, his political future in the U.S. Democratic Party is on the line.

The president's Tuesday remarks were another opportunity for him to assuage Democratic fears about his 2024 candidacy, following his disastrous debate performance against former President Donald Trump in June.

Since then, cracks have emerged within the Democratic Party as some lawmakers, donors and strategists publicly urge Biden to bow out of the race and allow a new nominee to step forward.

Earlier Tuesday, House Rep. Mikie Sherrill, D-N.J., joined the growing tally of Democratic lawmakers officially calling on Biden to drop out.

Others have expressed continued support for the president in public statements, while voicing their reservations behind closed doors.

Even as some Democrats remain tight-lipped about their concern about the president's electability, many have openly noted that this week's NATO summit comes with added pressure given the looming reelection doubts.

The summit presents a timely example of Democrats' heightened anxieties about losing to Trump in November. The former president has said he would consider pulling the U.S. out of the 32-member military alliance if he won a second term.

"Americans, they know we're stronger with our friends and we understand this is a sacred obligation," Biden said during his NATO speech.

Since his June 27 debate fumble, Biden has held several public appearances to try and restore confidence in his candidacy, including a 22-minute interview with ABC News last Friday. So far, his public showings have not put Democrats' worries to rest.

"The president needs to engage in the kind of interaction with voters that will prove to those that are skeptical out there that he can do the job," Sen. Chris Murphy, D-Conn., said in a Sunday broadcast interview about the week ahead. "If he can't do that, then he has a decision to make."

Biden is scheduled to hold a solo press conference on Thursday evening, a highly anticipated opportunity for him to prove that he can carry on an exchange with reporters in an unscripted environment.