From Deadline Hollywood:
This one is a shocker. Veteran crime drama Law & Order will not get its shot at history after all. I hear that after long deliberations, NBC has decided to cancel the long-running procedural, which will end its run at 20 seasons, tied with Gunsmoke. This is very surprising as NBC brass had indicated lately that they would bring L&O for a record-breaking 21st season. But with strong development, especially on the drama side, and soft ratings for L&O, NBC apparently opted not to keep the aging series, which spawned several successful spinoffs. The latest, Law & Order: Los Angeles, will launch next season. L&O's renewal by NBC was also contingent on securing a sizable commitment from the series' cable home TNT whose off-network deal for the show was up at the end of this season.

They have the best cast in YEARS, the writing has been terrific, and they are ONE year from breaking the record and NBC wants to cancel it? It makes no sense! 
