Democrats move to block Trump's border emergency

House Speaker Nancy Pelosi said the chamber will vote next Tuesday on the so-called disapproval resolution to terminate the national emergency that Trump declared last week, an exceptional step that sparked fierce political and legal battles.

The legislation is expected to clear the Democrat-held House of Representatives, then head to the Senate where it is guaranteed a vote under the rules. Its fate however is anything but assured in the upper chamber, which is controlled by Trump's Republicans.

Trump swiftly weighed in to say he would reject the measure if it reaches his desk, deepening a showdown with his Capitol Hill opponents.

"Will I veto it? 100 per cent," Trump said, expressing confidence that Congress would not be able to override his objection.

Overriding a presidential veto requires a two-thirds majority in both chambers, meaning substantial numbers of Republicans would have to break with Trump in order for his emergency declaration to be blocked.

Pelosi meanwhile hammered away at Trump's "lawless" declaration, saying it had no valid rationale.

"There is no evidence to support the president's false claim of a crisis on the border," Pelosi told a conference call Friday from Laredo, Texas, where she and fellow lawmakers were visiting a bridge connecting the US and Mexico.

Trump announced the emergency last week in order to bypass Congress, which did not approve the USD 5.7 billion he wanted for his wall, a longstanding promise from his 2016 presidential campaign.

The spending bill, which he reluctantly signed in order to avert a government shutdown, included appropriations of just USD 1.4 billion for fencing and other barriers along the border, but specifically not for Trump's proposed wall.

Democrats -- and some wary Republicans -- condemned Trump's unilateral move as an effort to usurp the powers of the purse, which under the US Constitution are reserved for Congress.

"We do not have a monarch, we have a separation of powers in our country," Pelosi said, adding she was urging Republicans to join Democrats in pushing back against the president.

The call to action comes as Trump and the White House press on with plans to re-purpose more than USD 6 billion from other sources, mostly already-allocated funds in the Defense Department budget.

Trump has repeatedly declared that rampant illegal immigration is fuelling a crisis along the border, leading to higher crime and strains on public services such as health care.

Congressman Joaquin Castro cited low levels of illegal immigration and record levels of national security resources at the border to boost the argument that Trump's emergency declaration was unnecessary, and "an unconstitutional power grab."

Castro, who chairs the Congressional Hispanic Caucus, said his resolution already has at least 226 co-sponsors, including one Republican -- beyond the simple majority needed in the 435-member body.

He said he would keep calling Republicans to build support for the measure and to urge lawmakers to send a bipartisan message to Trump.

"If the Congress rolls over on this, the president is likely to do it again," warned Castro.

Days earlier, 16 states filed suit against the Trump administration, saying the emergency declaration violated the US Constitution's assertion that Congress is the final arbiter of public funds.

The White House has remained consistent in its position that the emergency order empowers Trump to reallocate funds.

Military officials said some 6,000 active-duty troops and 2,300 National Guard members will be positioned along the border beginning March 1, helping install an additional 140 miles (225 kilometers) of concertina wire.

The states' lawsuit countered that tapping military money would result in huge losses for the states' National Guard units which would otherwise use the dollars for counter-narcotics activities and law enforcement.

Pelosi noted that a genuine emergency would secure support from Congress and the American people, but that Trump was merely declaring one in order "to honor an applause line in a rally."