if by that you mean failed almost 100% of the time in Iraq the first time yes. It realy was a failed system though improvements have made it workable now. funny how the media showed a near 100% kill ratio for it in the first gulf war then it turned out it was more like almost 0
Well it depends on how you define success. It was both a failure and a success at the same time, just depending on how you defined the objectives.
First, the Patriot missile was designed to shoot down aircraft, not missiles. Thus, it's mode of operation was to get near the target, and explode, using fragmentation or shrapnel to destroy the target. Great for aircraft.
But missiles are different. When the Patriot blew up near the scud missile, the missile itself might be blown apart, but the warhead, the actual explosive payload, many times still fell to the earth and exploded.
From the US military stand point, the target missile was 'hit'. If the goal was to knock the warhead off course, preventing it from hitting it's intended military target, then the Patriot was a success.
From the Israeli stand point, where the warhead still hit the ground and blew up, destroying peoples homes and harming civilians, it was considered a failure.
Both perspectives are correct. Both conclusions are accurate. The Patriot was both a success and a failure depending on which goal, and which view you choose.
However, as it relates to Chemical, Biological, or Nuclear warhead missiles, the Patriot is simply not designed for this, and will not be effective. A missile to missile intercept system must be designed to destroy the warhead. Allowing a nuclear warhead to still fall to earth undamaged, will of course be useless.
This is why the missile defense shield project is so vital.