Enemies of Paul Ryan's border adjusted corporate income tax (BAT), from retailers to conservative think tanks, have been mustering forces in recent weeks, arguing that the tax would hurt consumers while doing little to boost domestic employment.

But that tax reform, which would raise rates on importers while lowering taxes on exporters, does still have its supporters, including the CEOs of manufacturing firms like Boeing, Caterpillar, United Technologies, and Raytheon. Those executives cosigned a letter to lawmakers Tuesday along with 12 other industry leaders, supporting the tax as a "big and bold" reform that would "level the playing field for American workers" and "dramatically reinvigorate economic growth."

Why it matters: BAT supporters know that given opposition in Congress, supporters need the White House to weigh in in favor. The best way to do that is to frame the tax as a nationalist policy that would support American workers at the expense of foreign countries and multinational firms.