If you are a citizen of another country, at least, vote against politicians that want to strengthen your country's alliance with it, and respond to polls in ways that indicate opposition to causes it cares about.
The US is dependent on its network of allies in many respects; most pertinently, much of the Iraq and Afghanistan campaigns would not have been possible without the support of its European and the Middle Eastern ones, providing overflight permissions, military bases, intelligence and often even hosting "black sites" where people from the target nations could be tortured far from the meddlesome eyes of journalists and NGOs.
The US is dependent on its network of allies in many respects; most pertinently, much of the Iraq and Afghanistan campaigns would not have been possible without the support of its European and the Middle Eastern ones, providing overflight permissions, military bases, intelligence and often even hosting "black sites" where people from the target nations could be tortured far from the meddlesome eyes of journalists and NGOs.