As a presidential candidate, Donald Trump promised to collapse the current seven personal income tax brackets to three brackets. He repeated that call in a one-page summary of principles for his upcoming tax legislation released after he became president, on April 26, 2017.

In that summary, Trump said he would reduce today's seven tax brackets to three -- 10 percent, 25 percent and 35 percent.

When Trump initially proposed a somewhat different version of this plan during the 2016 campaign -- with three brackets of 12 percent, 25 percent and 33 percent -- the right-of-center Tax Foundation projected that the loss in revenue could range from $1.2 trillion to $1.4 trillion over 10 years.

We should note that there is no actual tax legislation yet to carry out Trump's priorities, and Congress will have to pass measures before Trump can sign them into law. Still, his decision to mention the proposal in the tax policy summary moves this promise to In the Works.