(CNN) On Wednesday afternoon, a 19-year-old brought an AR-15 weapon to a high school in Parkland, Florida. He allegedly shot more than two dozen people, killing 17. It was not the first mass shooting of 2018, and it was one of the 10 deadliest mass shootings in American history.

In the wake of the latest school shooting, a familiar blueprint took hold. Republicans expressed condolences for the victims. Democrats demanded action and scolded Republicans for their inaction. President Donald Trump tweeted. Journalists cited statistics on the number of school shootings. Polls were shared that showed strong support for things like universal background checks. And people wondered openly whether this time would change anything.

"Lots of people lamenting 'nothing will change' today," tweeted Connecticut Sen. Chris Murphy , a Democrat and leading gun control advocate. "That's what people said before the Montgomery boycott. That's what people said before Stonewall. Change happens, if at the moment when it seems most unlikely, you decide to do more."

That's a hopeful and important sentiment. And, Murphy is right. Nothing changes until everything does.

But, if past is prologue, this shooting won't change much of anything. Here's a list of what likely won't change -- in no particular order than how I thought of them:

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