GOP lawmakers discuss vote to block Trump's new tariffs on Mexico, in what would be its first real act of defiance

The vote, which would be the GOP's most dramatic act of defiance since Trump took office, could also have the effect of blocking billions of dollars in border wall funding that the president had announced in February when he declared a national emergency at the southern border, said the people, who spoke on the condition of anonymity because the talks are private.

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Trump's plans to impose tariffs on Mexico -- with which the United States has a free-trade agreement -- rely on the president's declaration of a national emergency at the border... Congress passed [a blocking] resolution in March after Trump reallocated the border wall funds, but he vetoed it. Now, as frustration on Capitol Hill grows over Trump's latest tariff threat, a second vote could potentially command a veto-proof majority to nullify the national emergency, which in turn could undercut both the border-wall effort and the new tariffs.