Republican presidential candidates participate in the Fox Business Network Republican presidential debate at the North Charleston Coliseum and Performing Arts Center, Jan. 14 in North Charleston, South Carolina. Scott Olson/Getty Images

Many of the Republican presidential candidates lashed out at President Barack Obama for his use of executive orders during Thursday night’s debate. Florida Sen. Marco Rubio said that if he is elected president, he would repeal all of President Barack Obama’s “unconstitutional” executive orders on day one.

Former Florida Gov. Jeb Bush and Donald Trump also criticized the president, with Bush saying the orders were “illegal” and Trump saying executive orders were not how the president was supposed to operate. This is a common concern about Republicans, who have frequently complained that Obama has abused his executive power.

Rubio has said before that he would repeal Obamacare, as well as reverse the president’s executive orders such as the one barring anti-LGBT workplace discrimination among federal contractors. Both Texas Sen. Ted Cruz and Bush have also said they would make reversing Obama’s orders a top priority.

Obama has used executive orders to take actions in areas where he has not been able to work with Congress, such as on immigration and and gun control. While conservatives have questioned his power, most fact-checkers and have ruled that Obama has not overstepped his powers.

While some have also claimed that Obama has issued more executive orders than is normal, he has in fact issued fewer orders than former Presidents George H.W. Bush, Ronald Reagan, Bill Clinton and more, according to an analysis by FiveThirtyEight.

Thursday night’s Republican debate marked the first time GOP candidates faced each other in person since the start of 2016 and it also came as attacks between the candidates have been heating up on the campaign trail. With just weeks to go until the first nominating contests in Iowa and New Hampshire, Republican front-runner Trump has been lashing out at his rivals more than ever, and opponents like Cruz have been hitting back.

Trump has maintained his lead in the national polls even as Cruz has surged in Iowa and the group of more moderate Republican candidates eye New Hampshire. Ahead of Thursday’s debate, Trump stood at 34.5 percent, followed by Cruz at 19.3 percent and Florida Sen. Marco Rubio at 11.8 percent, according to Real Clear Politics’ average of national polls.

While Fox Business Network was expected to focus many of its questions on economic issues Thursday night, the candidates were hitting each other particularly strongly on national security and immigration this week. Many of the questions on Thursday led the candidates to criticize Obama and other Democrats at least as much as each other.