Republican National Committee Chairwoman Ronna McDaniel speaks at a fundraiser in New York on Dec. 2, 2017. (Susan Walsh/AP)

The Trump era has exacerbated internal rifts within the Republican Party. Now, it is opening another divide within one of the GOP’s most important families.

Mitt Romney’s decision to publish a Washington Post op-ed Tuesday night criticizing President Trump’s character was met with a somewhat tempered response Wednesday morning from Trump himself, who urged the 2012 GOP nominee and Utah senator-elect to be a team player.

It faced a harsher response from Romney’s own niece, who happens to be chairwoman of the Republican National Committee.

“POTUS is attacked and obstructed by the MSM media and Democrats 24/7,” Ronna McDaniel tweeted. “For an incoming Republican freshman senator to attack @realdonaldtrump as their first act feeds into what the Democrats and media want and is disappointing and unproductive.”

That McDaniel has gone down this road is not hugely surprising. The RNC is the political arm of the White House, and there was undoubtedly pressure on McDaniel to do what is expected of someone in her position. Romney leveled some pretty harsh charges, writing that “the president has not risen to the mantle of the office.” It is McDaniel’s job to advocate for Trump.

McDaniel also clearly made her decision on Trump vs. her uncle long ago, and not just by taking the RNC job. After Romney vocally criticized Trump throughout the 2016 campaign, The Post reported that Trump asked McDaniel to drop “Romney,” the maiden name she used for years in Michigan politics. McDaniel acceded. That surname rarely appears in official RNC documents or McDaniel’s media appearances.

But the harshness of McDaniel’s comment is notable. She is not saying, like Trump, that her uncle should join the team; she is calling what Romney did “disappointing and unproductive.” She is suggesting he is doing the dirty work of Democrats and the mainstream media. She even conspicuously refers to him as an “incoming Republican freshman senator,” diminishing his political clout and hinting that he should know his role. This is the 2012 Republican nominee for president, but she is shrugging him off as a backbencher.

It is not “My uncle is a terrible person,” but it is pretty strong stuff, and it makes clear that Romney’s potential leadership of the anti-Trump wing of the Republican Party will come with some repercussions — including from his own kin.

It is also a fitting development for the Trump era. The 2018 campaign was marked by several examples of members of a family actively campaigning against one another. One of Trump’s own top advisers, Kellyanne Conway, has a husband who has been among Trump’s most outspoken critics. And perhaps the biggest family name in GOP politics right now — the Bushes — has also been rendered somewhat split, with former president George W. Bush and Trump’s 2016 opponent Jeb Bush opposing Trump but Jeb’s son George P. Bush, who is building a political career in Texas, embracing the current president.

It is a reminder that in politics, ambition often trumps blood. But given that these families are usually in the same party, those choices do not usually need to be made. Trump’s bull-in-a-china-shop approach to politics and Romney’s decision to begin his Senate tenure with a bang left McDaniel with no choice but to say something. And she said a lot.