President Biden is set to hold a campaign rally in Michigan on Friday following a news conference that received mixed reviews from other Democrats, in which Biden showed command of complex foreign policy issues but stumbled through some answers and mixed up names.

The Thursday night news conference did not immediately halt the stream of Democrats who have been calling on Biden to end his candidacy after a rocky debate performance two weeks ago. Shortly after the news conference ended, Reps. Jim Himes (D-Conn.), Scott Peters (D-Calif.) and Eric Sorensen (D-Ill.) added their names to those who have asked Biden to step aside.

But other Democrats who were previously critical of Biden commended his clear grasp of foreign policy and global economics. The array of responses suggests that the next 24 to 48 hours may be critical to determining Biden’s political future, adding to the drama surrounding the president’s performance in Michigan on Friday.

Hours before the news conference, four more Democratic House lawmakers had already called on him to step aside, voicing fears that he would have difficulty defeating presumptive Republican nominee Donald Trump because of voters’ concerns about his age. Biden is 81 and Trump is 78, but polls suggest voters are significantly more worried about Biden’s capacity than Trump’s.

Many Democrats predicted privately that defections could increase markedly on Friday. Some in the party were waiting for the end of the NATO summit in Washington and others were holding their fire until the news conference.

Biden began the question-and-answer session by touting his accomplishments at NATO and his record as president, providing an implicit defense of his continued candidacy. But early on, he mistakenly referred to Vice President Harris as “Vice President Trump,” a verbal slip-up that elicited audible gasps in the room and frustration from already nervous Democrats.

But Biden also gave lengthy, complex answers to a range of foreign policy questions and argued forcefully that he is the most qualified person to defeat Trump and govern the country. Still, given the view of many Democrats that Trump presents an existential threat, they may be unwilling to take that risk.

Democrats have feverishly debated whether Biden should remain their presidential nominee since a debate performance on June 27 — when he stumbled over words and sometimes struggled to complete sentences — brought to the fore long-simmering concerns about his physical and mental fitness. Biden so far has been unmoved by the growing calls from within his party for him to exit the race.

The president’s visit to Michigan could also highlight another key political vulnerability, one that was bedeviling his campaign well before the June debate: Arab Americans, Muslims and liberals deeply angered by his response to Israel’s war in Gaza who have said they will withhold their votes because of his failure to call for a permanent cease-fire and cut off U.S. military aid to Israel.

More than 38,000 Palestinians have died in the enclave in the past nine months. Israel launched a punishing military assault in Gaza after Hamas militants crossed the border into Israel last Oct. 7, killing 1,200 people and taking some 250 hostage.

Michigan is home to the country’s largest Arab American population, with about 300,000 people who claim ancestry from the Middle East or North Africa. Michigan’s Arab and Muslim community overwhelmingly supported Biden in 2020, when he won the state by 154,000 votes.

Abdullah Hammoud, the mayor of Dearborn — where Arab Americans make up the majority of the population — said he has not spoken to White House officials for several months about his constituents’ concerns over the war in Gaza. Even as Gaza has receded from the headlines in recent weeks, Hammoud said, the situation on the ground has continued to worsen and residents have not lost focus on the issue.

“Earlier this year, the president sent his senior White House officials to listen to the constituency he sought support from four years ago, and there have been no meaningful steps since. Things have only gone backwards,” Hammoud said, referring to a Feb. 8 meeting in which senior national security officials visited Dearborn and met with the mayor and other officials.

“We’re looking for a president with the backbone to call for a cease-fire,” Hammoud added. “This is not the president that was promised to us four years ago.”

Most public polls show Biden trailing Trump in Michigan, which is key to the president’s narrowing path to victory — he has few, if any, paths without it.

The Biden campaign argued in a memo obtained by The Washington Post on Thursday that it can win by focusing on the “blue wall” states of Michigan, Wisconsin and Pennsylvania.