Is it wrong that I'm going to purposely ruin my longest friendship simply because I felt like it?
Yes, that seems inappropriate. Why would you want to ruin in?
It's time for my smear campaign.
It sounds like you are just vengeful. It's shameful to destroy a friendship for little or no reason. It's best to rekindle your friendship while you can.
Bullshit. It's the best thing I've ever done.
Consider the reasons for wanting to end a friendship before you do. Destroying a friendship for no reason at all is wrong and will leave you with regrets for doing so.