Ten Democrats vying to be the next president sparred over issues like immigration and gun control in the policy-heavy first debate of the 2020 primary season, providing a glimpse at the issues that will define the race for the nomination over the months to come.

In the briskly paced debate, candidates explained their differences on health care, climate change and LGBTQ issues. The debate revealed some of the key differences between the candidates, who sometimes talked over each other while trying to make an impression on a crowded stage.

The candidates on the stage Wednesday night were Cory Booker, Bill de Blasio, Julián Castro, John Delaney, Tulsi Gabbard, Jay Inslee, Amy Klobuchar, Beto O'Rourke, Tim Ryan and Elizabeth Warren.

Although there was no clear standout in the debate, Elizabeth Warren, Cory Booker and Julián Castro received the most speaking time. In terms of questions, Booker, O'Rourke and Klobuchar each had eight directed to them, followed by Warren with seven and Castro with six.

The candidates did not fixate on President Trump, but his presence loomed over the stage, with each candidate using him as a foil to pitch their agendas. Senate Majority Leader Mitch McConnell was another Republican boogeyman on the debate stage.

The second night of the debate will get underway Thursday night.