‘Don and I, as well as many other crewmembers, had flown numerous ‘Tomcat Chase’ and ‘Eagle Bait’ sorties against our best fighters – the Navy’s F-14s and the Air Force’s F-15s,’ Col. Richard H. Graham, former SR-71 Blackbird pilot.
During its 24 years of service, the SR-71 Blackbird gathered intelligence in some of the world’s most hostile environments. The Blackbird evaded all 4,000 missiles fired at it and, to this day, remains the only US Air Force (USAF) aircraft to never lose a crewmember associated with it; whether in the air or on the ground.
The Blackbird was designed to operate at extreme velocities and altitudes: in fact, from 80,000 feet, it could survey 100,000 square miles of Earth’s surface per hour. Thus, achieving a radar lock on it was extremely difficult for any hostile fighter.
Nevertheless, according to former Blackbird driver Col. Richard H. Graham, USAF (Ret.), tells in his book The Complete Book of the SR-71 Blackbird: The Illustrated Profile of Every Aircraft, Crew, and Breakthrough of the World’s Fastest Stealth Jet, there were two fighters that could achieve (simulated) SR-71 kills, but only under certain conditions. “Don [Don Emmons was Graham Reconnaissance System Officer or RSO, the Blackbird back seater] and I, as well as many other crewmembers, had flown numerous ‘Tomcat Chase’ and ‘Eagle Bait’ sorties against our best fighters – the Navy’s F-14s and the Air Force’s F-15s. We flew the SR-71 to provide the fighters practice at finding, tracking, locking on, intercepting, and simulated firing of their sophisticated F-14 Phoenix missiles and the F-15’s Sparrow missiles at a high altitude, high speed target. The Tomcat Chase missions were flown over the Pacific Ocean and Eagle Bait missions in the Nellis AFB training area, north of Las Vegas, Nevada.”

Graham continues. “To maximize scarce, high altitude/high-speed intercept practice for the fighters against the SR-71, we stacked the deck in their favor to avoid a multitude of missed intercepts, and consequently, wasted time. The intercepts were conducted in a very controlled environment, favoring a successful outcome by the fighters. […] Even under these highly controlled flying conditions, the F-14s and F-15s had extreme difficulty achieving a satisfactory SR-71 kill.
American fighter pilots were able to lock on the SR-71 only after the Blackbird crew turned off their defensive countermeasures.
It was just about impossible to achieve a lock on the SR-71 unless she was injured.
SR-71 pilot Dave Peters adds some interesting and hilarious details.
‘One of the interesting discoveries from those missions, especially the Eagle Bait, was that they couldn’t even find us when everything was shut down and we told them exactly where we were. It was then realized that the F-15 had a speed gate on their radar at 1500 kts. We were casually warping along from 1850 to 2000. So, for them, we didn’t exist. We flew them fairly regularly from about 82 and they were still doing them after I retired in 86. We flew the Eagle Bait with the F-15s and Tomcat Chase with the F-14s. The 14s could find us but they couldn’t do anything until we modified and gave them times, route of flight, speed and altitude beforehand so they could have a pre-planned setup. The 15s didn’t do that well for quite some time.

‘Another mission we flew that was interesting was to come in over the California coast at speed and altitude to give the air traffic controllers an idea of what they would see on a space shuttle approach.
‘There was some animosity at first with both the Eagles and the Tomcats because they kept accusing us of not showing up. It was fun in the vain as the LA speed story, except it’s true, because we were on the same frequency with them and could listen to all the bitching because we didn’t show up. They got a little huffy because nobody told them we weren’t coming.’
Be sure to check out Linda Sheffield Miller (Col Richard (Butch) Sheffield’s daughter, Col. Sheffield was an SR-71 Reconnaissance Systems Officer) Facebook Page Habubrats for awesome Blackbird’s photos and stories.
Photo credit: U.S. Air Force

The premise of your title is wrong. The reason the SR72 could not be acquired is its stealth. It may be fast but it is míot faster than 186,000 miles per second which is the speed of light, which is how fast it would have to be to out run radar.
SR-72?