US President Donald Trump declared a national emergency at the Mexico border on Friday, a move which will allow him to bypass Congress and divert government funds towards his much vaunted border wall.

The decision is drawing widespread criticism, with senior Democrats and Republicans accusing him of gross abuse of power.

Trump says the wall is needed to stop drugs, gangs and criminals entering the US, but the number of undocumented migrants crossing the border is at a 20-year low.

And the government's data shows up to 90 percent of heroin, cocaine and methamphetamines is trafficked through official entry points.

Trump's declaration is already facing legal challenges. So could his apparent obsession with the wall push the US towards a constitutional crisis?

And how would that affect the Trump administration?

Presenter: Adrian Finighan

Guests:

Charles Moran - Republican strategist and Trump delegate 2016

Jeff Hauser - Executive director, Revolving Door Project at the Center for Economic and Policy Research

Bruce Fein - Political analyst and former US associate deputy attorney general

Source: Al Jazeera News