Complex sentence: By January 1976 the guerrilla presence in Tucumán had been reduced to a few platoons, and the military, fully backed by the local "élite" and the United States, was biding its time before seizing power.
Split into simpler sentences: By January 1976 the guerrilla presence in Tucumán had been reduced to a few platoons. In the meanwhile, the military, fully backed by the local "élite" and the United States, bided its time before ultimately seizing power.