The reason that people don't support bans on guns isn't that they don't think mass shootings might happen, so mass shootings happening don't change their opinion on whether guns should be banned.<p>A mass shooting happening doesn't really change anybody's calculus. The people who want to ban guns have wanted to ban guns well before [latest event], and the people who don't aren't persuaded by [latest event]. [latest event], however tragic, is rarely materially different from what has come before.