Republicans ignore Trump's policy whims

Republicans in the US Congress have learned to ignore President Donald Trump's policy whims, knowing whatever he says one day on guns, immigration or other complicated issues could well change by the next.

But Trump's decision to seek steep tariffs on steel and aluminium imports has provoked rarely seen urgency among Republican politicians.

They're scrambling to convince the president he would spark a trade war that could stall the economy's recent gains if he doesn't reverse course.

The issue pits Trump's populist promises to his voters against GOP free trade orthodoxy and the interests of business leaders.

Unlike recent immigration and gun policy changes that require legislation, Trump can alter trade policy by executive action, intensifying the pressure on lawmakers to change his mind before he gives final approval for the penalties.