Russian intercepts of Western signal intelligence aircraft isn't anything new. It's been happening going back to the Cold War, and there have even been minor diplomatic incidents over it. But this is a video of it actually happening with an Su-27 fighter jet and a Portuguese P-3 Orion, and it's incredibly tense.
As it should be, when a guy flashes the underside of his plane at you, packed with air-to-air missiles, like someone flashing a gun at you under their coat on the subway.
While it's not unusual, in any sense, for a Russian jet to identify and escort a NATO plane skirting Russian airspace over the Baltic Sea, it is unusual for us to have such high quality video of it. Though it shouldn't be surprising, considering how many sensors the P-3 Orion that shot this video is bristling with. You would think a few cameras would be included in that bunch, anyways.
The Aviationist, which originally posted the video, notes that the Su-27 hits the airbrakes once it finally catches up to the slow-moving turboprop-powered P-3. Once it makes sure the Portuguese crew is aware of the situation, it peels off.
The message the fighter jet was intending to deliver is already received, loud and clear.
Big hat tip to ttyymmnn on Oppo!