There is also SBIRS and radars across Saudi Arabia. By far the likeliest scenario is that the US detected the attack and made the choice not to defend Qatar.
You'd need air launched ballistic missiles (which Israel used) to avoid detection by Saudi radars. The Houthis don't have those.
You'd need jets capable of operations over the Red Sea - which the Houthis don't have.
If they did have those things, they'd certainly use them to attack Israel or Riyadh, not Qatar.
You don't need jets to go over the Red Sea either, Houthi cruise missiles can operate over the Red Sea and then change course to hit their targets.
You do if you want ALBMs… the “A” is pretty important for that acronym.
And cruise missiles are not ballistic missiles. Cruise missiles that tracked up the Red Sea and then crossed 1,200km of Saudi Arabia while heading for Qatar would obviously be detected (and likely shot down) by US and Saudi air defenses.
Due to the curvature of the earth, such a cruise missile attack would almost certainly not be detected until it got close to Qatar.
Hence why Israel used ballistic missiles that likely reached 30+ km in altitude over Saudi air space and impacted in less than 15 minutes after launch.
This is why cruise missiles and drones fired from Yemen routinely hit their targets in Israel, in fact that happened just yesterday.
Israel used ballistic missiles in all likelihood because those are the weapons that Qatar needs American help to intercept.
These missiles are not especially fast given the distance they have to cover. They were in the air for 10+ minutes, more than enough time to cross check IR early warning and radar tracks.
I should clarify that it is ENTIRELY possible that you are correct. It is entirely possible the US made a choice to not intercept here. My point is that it is also entirely possible that the US didn’t make a choice. I just don’t see enough clear data to tell. I also think that, even if it was a choice, it was probably more of a split-second decision made by lower-level officers on the ground as it happened, rather than a carefully-considered decision made by national security leadership.
The chain of actions you're describing would have around 10-15 minutes to be executed.
The likelihood that neither THAAD nor any of the Patriot batteries were sufficiently ready to launch is also basically zero.
THAAD has an engagement range of over 100km, so the battery was undoubtedly in range; and it can cue Qatar's own Patriot batteries so they can launch the missiles; I find it hard to believe there were none in Doha.
So, this would not be a split-second decision - there was quite a bit of time given the proposed trajectory. It's very very unlikely the US didn't have the sensors to see the missiles given the intense concentration of long-range ABM radars in the region.
Is it theoretically possible the US legitimately couldn't do anything? Yes. But the odds are overwhelming that the US knew about the strike with minutes to spare before making a decision, and decided not to protect Qatar.
"Oh no, our whole city was destroyed and we couldn't do anything because they changed the tuning on their missiles a day before."
Mega LMAO, the things one reads these days.
The TPQ-36 has a 90º azimuth - it can literally only look in 1 direction. (https://en.wikipedia.org/wiki/AN/TPQ-36_Firefinder_radar)
For fixed threats - e.g. detecting Iranian strikes, the TPS-80 radars are made to be stationary to provide better coverage/resolution of the direction of incoming missiles.
The US uses satellite systems that can detect ground-launched ballistic missiles - and if we're looking with our AEW&C, we can likely see an air-launched one, but we had no reason to be looking for air-launched ballistic missiles over the Red Sea.
Don't take my word for it..
> The Israeli Air Force (IAF) fighters were over the Red Sea when they fired air-launched ballistic missiles, an unnamed U.S. defense official told the Associated Press. In this way, Israeli aircraft didn’t need to enter the airspace of any Middle East country, and the missiles arrived from a direction that the air defenses in Qatar were not focused on looking. The missiles would have also passed over Saudi Arabia at very high altitudes, likely outside the Earth’s atmosphere.
https://www.twz.com/air/new-info-on-how-u-s-military-was-cau...