President Donald Trump delivers remarks at the National Prayer Breakfast in Washington, U.S., February 2, 2017. REUTERS/Carlos Barria I've written before about the political brilliance of President Donald Trump's public tussling with companies.

Principled conservatives may fret about the government getting too involved in corporate decisionmaking. But when the president gets on the phone and demands that CEOs produce their products in America, or stop charging taxpayers so much for fighter jets, he's sending a popular message that he's fighting for regular people.

However.

This shtick will become much less effective if he is seen using the bully pulpit of the presidency not to demand that companies give a fair shake to workers or taxpayers, but that they do favors for his family.

And so inevitably, Trump took to Twitter today to harangue Nordstrom about their decision to drop his daughter's fashion line:

(Nordstrom, for its part, says they dropped Ivanka's line "based on the brand's performance." Sad!)

There are all sorts of areas for concern about conflict of interest and self-dealing between Trump's public duties and his family's business interests. But this is the first time during his presidency that Trump has actually scolded a company for failing to do business with his family.

You can expect to see this thrown back in Trump's face the next time he pulls his Corporate Avenger bit — exactly whose interests is he looking out for when he slaps around corporate America?