…What do Rand Paul, Susan Collins and John McCain have in common? Very little.

The press corps is busy quizzing the president, the speaker of the House and the Senate majority leader on their plans for tax reform. The question is why they aren’t chasing after the three people who actually hold all the power.

If the past eight months have proved anything, it is that all the 24/7 news coverage of Donald Trump’s antics, all the millions of words devoted to Paul Ryan’s and Mitch McConnell’s plans, have been a complete waste of space and time. In the end, control of the entire policy agenda in Washington comes down to three senators. Three senators whom most Americans have never had a chance to vote for or against. Three senators who comprise 8% of their party conference. Arizona’s John McCain, Maine’s Susan Collins and Kentucky’s Rand Paul. Forget Caesar, Crassus and Pompey. Meet the Never-Trump Triumvirate.

At least the House Freedom Caucus scuttles GOP legislation based on shared principles. Sens. Ted Cruz and Mike Lee have also led revolts against bills, again based on shared criticisms. But what do the Arizona maverick, the Maine moderate and the Kentucky libertarian have in common? Very little.

Well, very little save motivations that go beyond policy. And that is the crucial point that is missing from the endless analyses of the McCain-Collins-Paul defections on health care. The media has treated the trio’s excuses for killing their party’s top priority as legit, despite the obvious holes in their objections over policy and process. What in fact binds the three is their crafting of identities based primarily on opposition to their party or Mr. Trump. This matters, because it bodes very ill for tax reform in the Senate. Overcoming policy objections is one thing. Overcoming egos is another.

Mr. McCain, who is gravely ill with brain cancer, has decided his final legacy will be a return to the contrarian “straight talk” persona of old, which wins him liberal media plaudits. The Arizonan has never gotten over losing the presidency, and it clearly irks him that Mr. Trump succeeded where he failed. His personal disdain for the president is obvious, and his implausible excuses for opposing the Graham-Cassidy health-care reform are proof that this is personal.

Ms. Collins is reportedly days awa y from deciding whether she’ll ditch the Senate gig and run for governor. That potential campaign has guided her every move for at least a year now—perhaps her entire career—and was clearly among her reasons last summer to abandon her party’s nominee and publicly excoriate Mr. Trump. It is a basic precept in Washington that Sen. Collins votes in whatever way best serves Sen. Collins. Right now that means being Never Trump.

Mr. Paul worked hard during his first Senate campaign to reassure Kentuckians that he was not his father, and it turns out that’s very true. Because even Ron Paul was to be found with his party’s House majority on issues that truly mattered, and largely saved his defections for the lost causes that produced 434-1 votes. Sen. Paul’s standards for “conservative” policy are as varying as the wind, and lately they blow toward whatever position can earn him the title of purest man in Washington.

The press was fixated this week on Mr. McConnell’s bad week, which is an easy piece to write. But it ignores the obvious reality that the Triumvirate seems to have never had any intention of letting its party succeed. After all, a senator who intended to stand firm on “regular order,” as Mr. McCain said, would have informed his colleagues of that demand at the beginning, rather than allow his colleagues to set up for another vote and then dramatically tank it (again) at the last minute. A senator who voted for “skinny” ObamaCare repeal in the summer on the grounds that anything was “better than no repeal,” in the words of Mr. Paul, would not suddenly engineer an unreachable set of demands for his vote on an even better repeal.

The Senate has no lack of lime-lighters. Nor is it low on Trump critics. Think Nebraska’s Ben Sasse and Arizona’s Jeff Flake. The difference is that the clear majority of the critics aren’t allowing ambition or disdain get in the way of votes for better policy.

But this raises the question of whether the White House understands that the Triumvirate is also the prize on tax reform. Mr. Trump took a shot at Mr. McConnell this week, but the president needs to shift his focus to those who hold the actual power. Those dinner invites to Chuck and Nancy would be better reserved for Ms. Collins. Its internal conversations need to focus on what forms of flattery or policy or misery might appeal to the political motivations of Messrs. McCain and Paul, and get them on side.

Because the Triumvirate made very clear during the health-care debate how it operates. Pretending it won’t do it again is to ignore reality.