For those who argued that Donald Trump’s foreign policy views were dramatically different from those of his predecessors, the skeptics always had a ready answer: John Bolton. Now that Trump has unceremoniously dismissed his hawkish national security adviser, that could pave the way for the change that Trump had promised and that the public anxiously wants.

Over the course of his presidential campaign, Trump was rewarded for his willingness to challenge the policy elite. He even railed against the Iraq War, initiated by a Republican president, in a Republican debate in South Carolina — and won the primary there. Unlike nearly all of his rivals, Trump correctly sensed that Americans were disinclined to spend vast sums, and risk the lives of American troops, on regime-change wars and costly, open-ended nation-building projects abroad.

In a major foreign policy speech delivered as he was closing in on the GOP nomination, Trump explained that “foolishness and arrogance [had] led to one foreign-policy disaster after another.” And he pledged “to shake the rust off America’s foreign policy” and “invite new voices and new visions into the fold.”

But, once elected, he did nothing of the sort. Instead, he populated his administration with people committed to maintaining the status quo, including H.R. McMaster as national security adviser, Jim Mattis as secretary of defense, and John Kelly as secretary of homeland security, later White House chief of staff.

To be sure, these establishment figures occasionally steered Trump away from bad — and perhaps even disastrous — decisions. McMaster, Mattis and Kelly, along with Secretary of State Rex Tillerson, delayed, but ultimately couldn’t derail, Trump’s single-minded desire to leave the Iran nuclear deal. Bolton’s most enduring achievement, albeit a dubious one, may be in working with Tillerson’s replacement, Mike Pompeo, to set the United States on a possibly irrevocable path to war with Iran.

The next national security adviser will be judged by his or her ability to translate Trump’s “America First” vision into concrete action. That will involve countless decisions, starting with the appointment of like-minded personnel to staff up the National Security Council, and the removal of Bolton acolytes.

But the immediate policy priority should be extricating the United States from the 18-years-long war in Afghanistan. When Trump set about to fulfill his campaign promise to quit the conflict, he encountered near unanimous opposition from senior national security officials. When he increased the number of U.S. troops on the ground there, he pinned the blame on his advisers.

“We’re there,” he told the Washington Post, “because virtually every expert that I have and speak to [says] if we don’t go there, they’re going to be fighting over here.” Although nearly two thirds (64%) of Iraq and Afghanistan war veterans have decided that the wars were not worth fighting, Trump’s brain trust concluded, erroneously, that there was no alternative.

Bolton, like his predecessor McMaster, appeared to agree with this sentiment. He even tried to thwart Trump’s bid to get out of America’s longest war by undermining peace talks with the Taliban. He had similarly thrown cold water on the Trump administration’s North Korea negotiations. The president deserves a national security adviser willing and able to execute his top policy priorities.

More broadly, however, the next national security adviser can perform an invaluable service by bending U.S. foreign policy to conform with modern realities — including the wishes of the American people. America’s ability to police the world, while others watch from the sidelines, was waning long before Donald Trump took up residence at 1600 Pennsylvania Ave. Indeed, we should welcome the fact that the world is now populated by many like-minded actors who are able to defend themselves from harm. The United States should be working diligently to reduce its permanent overseas military presence, stop intervening in the affairs of sovereign states, and shed some of the burdens of being the world’s sole superpower, so that it can attend to more urgent problems here at home.