Former President Barack Obama backed a slate of leading progressive Democrats in a second round of national endorsements released on Monday, a little more than five weeks ahead of the midterm elections.

Alexandria Ocasio-Cortez, who in June defeated incumbent Democratic Rep. Joe Crowley, the fourth-ranking House Democrat in their primary, received Obama's support this time around. Her name had been absent from the first wave back on August 1, a source of frustration to some on the left.

"The Democratic Party has always made the biggest difference in the lives of the American people when we lead with conviction, principle, and bold, new ideas," Obama said in a statement touting the candidates as a "movement of citizens who are younger, more diverse, more female than ever before."

The 260 hopefuls backed by Obama on Monday included a number of high-profile progressives who did not make his initial list, some of them because they had not yet won their primaries.

One notable omission: Minnesota Rep. Keith Ellison. The deputy chair of the Democratic National Committee is running for state attorney general amid allegations of domestic abuse by an ex-girlfriend. He has denied the allegations.

Florida Democratic gubernatorial nominee Andrew Gillum, the mayor of Tallahassee, was still four weeks away from his surprise primary victory when Obama rolled out his first slate of endorsement. Gillum, who was endorsed by Vermont Sen. Bernie Sanders before the vote, won the nomination on August 28 and is now facing off with former GOP Rep. Ron DeSantis, who resigned from the House weeks after the primary and is a fierce loyalist of President Donald Trump.

"Andrew believes that healthcare is a right, not a privilege, and he will make expanding Medicaid a priority on day one as governor," Obama said in a statement. Gillum, like Sanders, is a supporter of single-payer health care, but has put Medicaid expansion at the top of his to-do list if elected.

Obama also announced his support for Maryland gubernatorial candidate Ben Jealous, the former NAACP president and chief executive who endorsed Sanders over Hillary Clinton in the 2016 Democratic presidential primary. Jealous is trailing in the polls as he seeks to oust incumbent GOP Gov. Larry Hogan and has faced some push back from some of the state's moderate Democratic establishment.

"Ben Jealous is an accomplished civil rights leader, businessman, and advocate for working people," Obama said in a statement that touted Jealous's efforts as "a social impact investor" who has "worked closely with small businesses, creating jobs and building a more inclusive economy."

With Monday's endorsements, Obama is now backing Gillum, Jealous and Georgia's Stacey Abrams. If elected, each would become their state's first African American governor. Abrams would be the first African American woman to win the office anywhere in the US. Obama also endorsed Vermont's Christine Hallquist, who is seeking to become the country's first transgender governor.

Down the ballot, Obama is now publicly backing Jahana Hayes -- whom he once honored as the 2016 National Teacher of the Year -- in Connecticut's 5th Congressional District, Wisconsin's 1st Congressional District House candidate Randy Bryce, another close Sanders ally, and Kara Eastman, the progressive insurgent who surprised the establishment when she beat the former "Blue Dog" Rep. Brad Ashford in the primary for Nebraska's 2nd Congressional District.

"I am honored to have President Barack Obama's endorsement!," Eastman tweeted on Monday. "This endorsement comes at a time when many Americans are eager for change. Here in #NE02 our grassroots, people-powered campaign is working every day to make that change a reality. Thank you @BarackObama!"

In a statement accompanying the endorsements, Obama's office explained that the former President's choices were made to highlight candidates in close races, especially those at the state-level where the outcome could have an affect on future redistricting efforts. He prioritized his own campaign and White House alumni, like Lauren Baer, a Democrat who worked as a foreign policy aide in the administration beginning in 2011 and is now running to flip Florida's 18th Congressional District.

He also endorsed Rachel Crooks, who is running for a state representative seat in Ohio. Crooks accused Trump before the 2016 election of kissing her on the lips without her consent. She is one of at least 15 women to allege some kind of past sexual misconduct by the President. Trump has denied all the allegations.