South Carolina Gov. Nikki Haley. (AP Photo/Cliff Owen, File)

During Donald Trump's unlikeliest of runs for the Republican nomination and then the presidency, Nikki Haley and Mitt Romney were two of his loudest and most high-profile critics. Haley said Trump was “everything a governor doesn't want in a president.” Romney called Trump a “phony,” a “fraud” and a bunch of other names.

And now, just 15 days after Trump's stunning victory over Hillary Clinton, the president-elect appears on his way to installing both Haley and Romney in senior roles in his administration. Haley, the governor of South Carolina, has accepted Trump's offer to serve as the U.S. ambassador to the United Nations — a move that will elevate Lt. Gov. Henry McMaster to the top job in the Palmetto State. The Wall Street Journal is reporting that Romney, the party's 2012 presidential nominee, has moved into the pole position as Trump's pick for secretary of state.

After meeting with President-elect Donald Trump at Trump's golf course in New Jersey, Mitt Romney described it as 'thorough and in-depth discussion' on areas of the world with particular significance to U.S. interests. Trump said the meeting 'went great'. (The Washington Post)

“The New York businessman views Mr. Romney as the prototypical choice to be the nation’s top diplomat, and a group of advisers inside the transition are pushing him to select the 2012 Republican presidential nominee,” write Michael C. Bender and Damien Paletta. “Two people said Mr. Trump is inclined to select Mr. Romney.”

That's a remarkable turn of events for any politician but particularly one as openly loyal (and vengeful) as Trump. The president-elect has built his reputation — both in this race and his prior business life — on remembering everyone who has ever slighted him and holding grudges.

What gives then? The selection of Haley — and the possible Romney pick — suggest that Trump the president may be a different animal than Trump the candidate. That Trump the president understands that consensus-building and diversity in his Cabinet are more important than score settling.

Haley, for example, not only bashed Trump during the primary season but is also viewed very favorably by the same party establishment that Trump lambasted throughout his campaign. But if you are trying to show people that (a) the campaign is over and (b) you are a lot more magnanimous than people give you credit for, then that history is exactly the reason to pick Haley. Not to mention she is an Indian American woman from the South in her mid-40s, a major break from the older white men whom Trump has put forward as his Cabinet picks to date.

Picking Romney over former New York City mayor Rudy Giuliani would reinforce the idea that Trump is truly committed to expanding his senior advisers beyond just the people who were most loyal to him in the campaign. Giuliani quite clearly was that — serving as Trump's hype man at many of his major rallies and as a staunch defender of the Republican nominee on TV. And Romney was the furthest thing from supportive of Trump — delivering a much-publicized condemnation of the nominee as an unserious and dangerous figure in March.

But Romney is someone who has spent years thinking critically about U.S. foreign policy — most notably during his time as the party's nominee four years ago. Giuliani's foreign policy experience comes almost exclusively from his time as a private consultant to foreign governments. Picking Giuliani would be a clear reward for loyalty. Picking Romney would be a nod to the idea of a true meritocracy in the Trump White House.

Now. This is Donald Trump we are talking about. The man who has no problem acting one way (magnanimous, gracious) one minute and a totally different way (bitter, angry, vengeful) the next. Given his demonstrated tendency to veer unpredictably on issues and approaches, it's dangerous to predict that any one hire is indicative of anything — just yet.

But remember that Trump promised, relentlessly, to hire the best people if and when he was elected president. Most people rolled their eyes at such a pledge. But, naming Haley to a key post — and considering Romney for another — suggest that Trump might have been more serious and committed to that promise than anyone thought at the time.

That would be a very good thing indeed.