President Donald Trump,facing the prospect soon of the longest U.S. government shutdown in history,was considering declaring a national emergency that would likely escalate a policy dispute with Democrats over his proposed U.S.-Mexico border wall into a court test of presidential power.

To escape a political trap of his own making,Trump suggested strongly on Thursday that he might declare an emergency so that he can bypass Congress to get funding for his wall,which was a central promise of his 2016 election campaign.

Trump is demanding that Congress provide $5.7 billion in U.S. taxpayer funding for the wall.That is opposed by Democrats in Congress,who call the wall an ineffective,outdated answer to a complex problem.The standoff has left a quarter of the federal government closed down and hundreds of thousands of federal employees staying home or working for no pay.