When most of us last heard from former Republican presidential nominee Mitt Romney on the subject of President Donald Trump, it was to accept Trump’s endorsement for his U.S. Senate bid, something Romney previously said he would not do.

Romney tweeted on Feb. 19, “Thank you Mr. President for the support. I hope that over the course of the campaign I also earn the support and endorsement of the people of Utah.”

For many, this was another infuriating Romney flip-flop. Others saw it as the most terse response realistically possible for a GOP Senate nominee. (My own suggestion was to leave off the first sentence and simply respond to Trump’s tweet without either rejecting or accepting the endorsement.)

In any event, Romney decided on the Sunday before the GOP Utah primary to put out an op-ed. (”Where I stand on the Trump agenda,” The Salt Lake Tribune)

“I will support the president’s policies when I believe they are in the best interest of Utah and the nation,” he wrote. “I have noted, the first year of his administration has exceeded my expectations; he made our corporate tax code globally competitive, worked to reduce unnecessary regulations and restored multiple use on Utah public land. In addition, I am pleased that he backed away from imposing a 35 percent tariff on all foreign goods.”

The last item, of course, was a decision not to do one of the many bad things Trump has threatened, so I find it hard to give him credit for that one. The jury is still out on the corporate tax code (notice he did not rave about the individual tax giveaway to the rich); the others are garden-variety GOP conservative positions.

Before we go further, the danger here comes with straining to come up with something positive to say without proper context. Regardless of the corporate tax changes, the tax plan was ill-designed, spilled gallons of red ink, and aggravated the gap between rich and poor. It was overall a bad bill, and Romney should let us know whether the bill in its totality was a good or bad thing.

Continuing on, Romney lists some disagreements: “I have openly expressed my disagreement with certain of the administration decisions such as the withdrawal from the Trans-Pacific Partnership (TPP); I want more markets open for Utah and American goods. I also oppose broad-based tariffs, such as those proposed on steel and aluminum, particularly when they are imposed on our allies. I agree, however, with narrower penalties levied on companies or nations that employ unfair trade practices, such as China.”

Oddly, he does not list some of the most reckless and destructive moves — leaving Obamacare in place but making it more expensive, showering North Korean dictator Kim Jong Un with praise, and retaining Cabinet officials who engage in galling conflicts of interest and self-enrichment (taking their cue from a president who refused to divest himself of his holdings). I grant you Romney wasn’t listing all of his disagreements, but he will need to respond when asked about all of these additional subjects — and many more.

Then comes his knottiest declaration: “I have and will continue to speak out when the president says or does something which is divisive, racist, sexist, anti-immigrant, dishonest or destructive to democratic institutions. I do not make this a daily commentary; I express contrary views only when I believe it is a matter of substantial significance.” And that is a problem: By not speaking up when Trump does or says something horrible, Romney implicitly signals it is not of “substantial significance.”

Which of the following, I wonder, would Romney consider to be of “substantial significance”? Saying undocumented immigrants would “infest” the United States, smearing the FBI, throwing temper tantrums in the presence of allies, refusing to fire Environmental Protection Agency Administrator Scott Pruitt for rank corruption and botching the response to Puerto Rico after Hurricane Maria. Put me down for all of the above.

Perhaps Romney means that he will not initiate a statement on every outrage but will respond if asked. That is a fair compromise. However, voters in Utah and elsewhere are right to worry that Romney will let far too much slide for the sake of comity and will become another enabler, albeit a less slavish one than his Republican colleagues.

I would hope that once in office, Romney would see the folly of letting Trump’s conduct slide by on the grounds it does not reach the august level of “substantial significance.”

Romney need not worry about re-election (and may not even seek it), so why not do exactly what Sen. Jeff Flake, R-Ariz., has done? Flake is not shy about calling out the president whether the matter at hand is big and small.

And here’s the thing: With this president, something small is almost always a prelude to something of “substantial significance.”

Jennifer Rubin | The Washington Post