Barack Obama will not endorse a Democratic candidate in the primary race with the White House chief of staff Denis McDonough saying on Sunday (10 January) that the president would wait until a nominee was chosen. Reports over the summer had suggested that the president might have been interested in siding with one candidate during the primary race.

"We'll do exactly what has been done in the past, which is when the nominee will be set, then the president will be out there," McDonough told Chuck Todd on NBC's Meet the Press. The chief of staff also responded to questions over whether the president's New York Time's op-ed over gun control was a way to criticise Democrat candidate Bernie Sanders for his wavering support on the issue.

"This isn't only about the [presidential] primary," he said. "We've got a third of the Senate that's running, we've got all the House that's running, we've got state houses and governorships across the country where this is going to be an issue on the ballot." In his op-ed, Obama said that he would only campaign for candidates who supported gun reform.

This is not the first indication that the president has suggested he will become involved in the 2016 Senate races, particularly due to the issue of gun control. Obama recently announced a series of 10 executive orders to curb gun violence and sidestep Congress.

McDonough also said Obama has met with Sanders—the Independent senator for Vermont—"both with the Senate Democratic Caucus and privately." He referred to the Green Mountain state senator as "a leading senator in our caucus," NBC News reported. There are two other candidates running for the Democratic nomination, frontrunner Hillary Clinton and long-shot candidate Martin O'Malley.

Obama is not the first president to choose not to endorse a candidate during the primary race. President George W Bush did not endorse the Republican nominee in 2008 until 5 March, just as Arizona Senator John McCain had nabbed the ticket. According to Fox News, President Ronald Reagan did not endorse Republican nominee George H W Bush—who happened to be his sitting Vice President— until May 1988.