The people who damaged the park are to blame for their actions, but the door was opened by the shutdown. Government shutdowns are a terrible idea and should be avoided.
I hope that people who did the damage be prosecuted to the fullest extent of the law for the damage that they did. There are people stupid enough to download videos of themselves doing the damage... and I would like to see them lose bank balances, cars, real estate, and other assets.
I know a rule about enjoying the Great Outdoors from being a Boy Scout -- leave what you enjoyed in Nature in as good a condition as you encountered it so that someone else can enjoy it. I recognize that Donald Trump is far too undisciplined a person to have ever been a successful Boy Scout and that he might never have caught onto that concept.
Advice to anyone: if you want a souvenir from a National or state park, then bring your camera along and take some photographs.
We are finding out the hard way that the Trump style of leadership is an unmitigated disaster for America, the only good of the Trump administration going to insiders who profiteer from economic looting.
