The Everett Herald editorial board states it in the clearest terms possible – “Background checks save lives:”

It’s satisfying and reassuring when the facts confirm common sense.
When 59 percent of Washington state voters passed Initiative 594 last fall, most voted for the initiative with the conviction that it made sense, common sense, to make it more difficult for felons and others barred from owning firearms to get their hands on a gun by requiring background checks for all sales. I-594 closed what had been called the gun-show loophole, requiring background checks for those purchasing firearms not only at gun shops, but any sale, most notably those between private individuals.

What voters didn’t have to back up their convictions at the time was much in the way of data that showed how effective such a law could be. We’re starting to see that data now.

Read the full editorial here.