Barack Obama Ready to Speak Up if Donald Trump Threatens 'Core Values'

U.S. President Barack Obama has indicated he could break with tradition and speak out against Donald Trump when the businessman succeeds him.

Trump is set to become the 45th president in January when he takes over from Obama, who has served two terms. Outgoing U.S. presidents traditionally step back from public life and avoid commenting on their successor's presidency.

The Republican president-elect has alarmed some U.S. citizens with his choices for key cabinet positions, including Stephen Bannon, the former head of alt-right site Breitbart News, who Trump has appointed as his chief strategist.

"I want to be respectful of the office and give the president-elect an opportunity to put forward his platform and his arguments without somebody popping off," said Obama, speaking at the Asia-Pacific Economic Cooperation summit in Lima, Peru on Sunday, the BBC reported.

But Obama added that if Trump touched on an issue that he would be vocal against "core questions about our values and our ideals," adding "if I think that it's necessary or helpful for me to defend those ideals, then I'll examine it when it comes."

Obama's predecessor, George W Bush, has largely retired from public life since the current president succeeded him in 2008. Bush told CNN in 2013 that Obama had a "hard job" and "a former president doesn't need to make it any harder."

The current president said that he would extend the same professional courtesy offered him by Bush to Trump. Obama also added that he thought that the responsibility of being president would mean Trump would water down some of his controversial campaign promises.

The Republican made numerous outlandish pledges during his presidential campaign, including a temporary ban on Muslims entering the U.S. and building a border wall with Mexico, which the latter would be expected to pay for.

Trump has held a series of interviews with potential candidates for positions on his team over the weekend at his golf resort in New Jersey. The president-elect is reportedly considering former Republican presidential candidate Mitt Romney, who was defeated by Obama in the 2012 election, for the role of secretary of state, and retired general James Mattis, who headed up U.S. military operations in Iraq and Afghanistan from 2010 to 2013, as his possible defense secretary.