One alternative, though not as balanced, would simply have been to retain the F-4 The Navy eventually worked out the problems with the F-14, and the Tomcat became a superlative air defense fighter. Eventually, it even gained a ground-attack mission. The temperamental nature of the design, the collapse of the Soviet Union, and the success of the Super Hornet made the Tomcat superfluous by the 2000s, however, and the Navy now lacks a long-range interceptor. The main threats to carrier battle groups no longer come from flights of bombers, but rather from ballistic missiles, and no fighter has yet demonstrated much promise at the ABM mission. Nevertheless, the Tomcat contributed a core defensive capability during one of the critical periods of the development of the super carrier.