From the FB page of Seattle for Bernie

People in line at Key Arena!! Secret Service is going through EVERYTHING. Every pocket, every bag. The following items are NOT permitted: food, liquids, hard bottles, vape pens, selfie sticks, umbrellas, pepper spray, sharp items of any kind, guns, ecigs, marijuana... If you are in line and have ANY of these you can A) Get rid of them or B) Have them toss the items when you pass through security.
You will help the process run more smoothly and much faster if you do not have bags or purses. And backpacks measuring 14x14 or larger are not permitted.
There are no exceptions. Zero. Zilch. Nada. Zip.
** Update: Also, take off all metal before going through the metal detector. Let's help them do their job more efficiently to get us inside sooner.