Trump has directed his attorney-general to propose measures banning bump stocks, which turn semi-automatic weapons into fully automatic weapons, and which were used in the Las Vegas shootings last year. Trump has also said that he supports federal background checks for people buying guns, although we will have to wait and see whether Congress puts a bill on his desk to sign. It is easy to say you support something when it is up to other politicians to get the job done.
Use this example to show how public opinion could limit the influence of pressure groups, in this case, the mighty NRA, which have often been resistant to any form of federal regulation on gun ownership. You can also use this example to show how presidential power is in part affected by events and by popularity. Is Trump acting on gun control as a result of polls that show the public blame him (and Congress) for the the failure to take action on gun control?
Equally, you could use this example to argue the opposite point, that Trump is mainly blaming mental health for the tragedy In Florida, and that no proposals have been made by him to restrict the sale of the AR-15, the gun involved in that shooting. Without the influence of the NRA and the sway that it has with gun owners (and by extension their voting habits), wouldn’t Trump have gone further?