The commitment to fighting communism and the US's previous relationship with Holden Roberto trumped the opinions of the dissenters and the US continued to support the FNLA.  US weapons, foreign mercenaries, and Zairian and South African forces were unable to defeat the MPLA with their Cuban and Soviet allies and American involvement declined during the following years under the Carter administration.  The 1980 election of Ronald Reagan brought the US back into the fold of the Angolan Civil War, with continued support of UNITA. Though UNITA achieved some military victories with the help of the SADF, particularly at Cuito-Cuanavale in 1988 where they beat off a large attack by MPLA and Cuban forces, it became increasingly clear that neither side would gain an upper hand and that most of the military successes on both sides were due to the Cuban and South African forces.