Why do some rebel groups make urban advances while others do not? To explain these important movements, scholars tend to focus on features of the rebel groups that are either time invariant or slow moving. We focus on time-varying features of the government instead. We argue that as members of the government’s external support network become distracted with other foreign entanglements, this creates openings in the conflict opportunity structure for the rebels to advance on key urban locations within the country. We posit that rebels understand when the government’s supporters become entangled in serious militarized disputes abroad that pull their attention away from the civil war. During these periods, rebels advance on cities as the government’s capacity declines without strong foreign backing in place. Statistical analysis of all civil wars from 1989-2017 supports this argument.