Behind closed doors and to cheers from the National Rifle Association, he rolled back an Obama-era regulation that would have made it harder for people with histories of mental illness to buy guns.
In doing so, he prevented an estimated 75,000 names of social security recipients with mental illnesses, people who need help managing their finances, from being added to the national background check database.
Trumps latest excuse is problematic - and not just because of his hypocrisy.
The vast majority of those with mental illness are non-violent and only 3 to 5 per cent of violent acts can be attributed to those living with a serious mental illness.
Peter Ambler, the executive director of fun control group Giffords, told NBC News:
Trump is wrong - study after study show that stronger gun laws can save lives - and a hypocrite of the worse kind.
One of his first actions as president trashed a new regulation that would have prevented potentially irresponsible and mentally incompetent people from being able to buy guns.
Ambler maintained that Trump's comments do not suggest he will rethink rolling back Obama's gun-check rule, which received its share of criticism for singling out the disabled.
Blaming mental health is a tactic straight out of the gun lobby's playbook that's meant to paralyse Congress.
Donald Trump's goal is to make people think our leaders don't have the power to prevent gun violence.
Trump is yet to suggest any policy change that could meaningfully curb the shootings.