I would support the President
72000 deaths in 2018 from opioid overdose is a national emergency. 700,400 people, the projected number of people that will die of an opioid overdose from 2016 to 2025, is a national emergency.
39770 people dying from firearm injuries in 2016 is a national emergency. 5,790 children being wounded by a gun and 1300 children dying from gun violence in 2017 is a national emergency.
396579 people arrested for illegally crossing the Mexican border in fiscal 2018, a number lower than 3 of the last 5 years, many whom are voluntarily turning themselves in to Customs and Border Patrol agents to seek amnesty is not a national emergency. That is a problem that needs to be addressed through Congressional action such as the recently passed bipartisan legislation funding immigration courts, border security and drug interdiction efforts at border crossings.
I would support the President declaring a national emergency to reduce opioid overdose deaths, or gun violence deaths, but not a national emergency to build an unwanted and ineffective wall. The President may have the legal authority to declare a national emergency to address a problem, but a national emergency should exist and not be manufactured or falsified.
Republicans in Congress need to recognize that if they allow this national emergency to stand they will have to live with the consequences when this or other Presidents decide to ignore our constitutional process and decide to declare other artificial national emergencies that will allow them to appropriate money to spend in ways that Congress has rejected.