First and foremost, it is the responsibility of the President of the United States to keep Americans safe. It can be argued that our issues at the Southern Border are tantamount to a perpetual invasion. And with that invasion comes an increasing crime rate, drugs, disease and certain eventualities.
As long as the border is unsecured it is not a matter of IF another tragedy will occur as a result illegal immigration, but when?
When will another American Citizen meet their demise at the hands of an illegal immigrant?
When will another American Citizen die as a result of an overdose from using drugs laced with Fentanyl that were brought to America through the porous Southern Border?
The President can ABSOLUTELY use his power, granted under the "The National Emergencies Act" to allow him to declare a state of emergency.
He can do so WITHOUT seeking authorization from Congress and would be completely justified in doing so.
The president can ABSOLUTELY declare an "immigration emergency" under the Immigration and Nationality Act.
Trump would need to receive a request from the attorney general or head of a local government describing the specific immigration emergency and what is needed to address it. The president must then determine if an emergency exists and inform the House and Senate Judiciary committees.
An immigration emergency is defined as an "influx of aliens which either is of such magnitude or exhibits such other characteristics that effective administration of the immigration laws of the United States is beyond the existing capabilities" of immigration authorities "in the affected area or areas."
Although the "State of Emergency" can be called by the President, it can be ended by Congress via a joint resolution. So, the House Democrats would have to convince Senate Republicans, who still control the upper chamber, to join them in blocking Trump's move.
Something tells me that may be an issue for Democrats.