As far as the Second Amendment, guns rights advocates have long been operating under the erroneous assumption that "shall not be infringed" means "no law of any kind can be passed with any restriction whatsoever involving any kind of firearms". So should we all be allowed to have our own M1 Abrahams or Stinger missiles then?
It is the job of the Congress to pass laws and one major purpose of legislation is to keep the populace safe. The President has Constitutionally-granted "Presidential Power" that has come to be known as the "Executive Order"****. Presidents have been using it since Washington. These laws and orders are reviewable by the Supreme Court to see if they pass Constitutionality. The Supreme Court has in the past rendered decisions clarifying and enforcing the 2nd Amendment as is their obligation The Washington DC handgun ban they shot down comes to mind); it stands to reason that if a law or Order is passed that doesn't pass Constituional muster they will again act. This is how the system is supposed to work and how it has worked throughout history. Bottom line - all gun laws are not inherently unConstitutional despite what the gun nuts say. And I say that as an owner of several firearms myself.
**** From Wikipedia Aricle on "Executive Orders" : Although there is no constitutional provision nor statute that explicitly permits executive orders, there is a vague grant of "executive power" given in Article II, Section 1, Clause 1 of the Constitution, and furthered by the declaration "take Care that the Laws be faithfully executed" made in Article II, Section 3, Clause 5. Most executive orders use these Constitutional reasonings as the authorization allowing for their issuance to be justified as part of the President's sworn duties, the intent being to help direct officers of the U.S. Executive carry out their delegated duties as well as the normal operations of the federal government: the consequence of failing to comply possibly being the removal from office.
“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” - Mahatma Gandhi