Professor Mayhew identifies 18 clusters of actions between 1789 and 1988 when members of the US Congress mounted major oppositions against American presidential administrations, including the Senate-led anti-Vietnam War opposition of 1964-72, and the Watergate challenge of 1973-74. He lists the clusters in chronological order, and discusses seven of their properties which in his view are both interesting and revealing about the American regime. He mentions that from the vantage point of modern British politics, congressional oppositions of the sort he describes may be a messy and unappealing way to conduct public affairs, but concludes that they seem to be a stabilizing, not a destabilizing way to conduct affairs in the American context and that as long as this remains the case they are likely to continue.