Diamond and Storing were associated with conservative politics, and both largely accepted that description of their views. But we must recall that both died in 1977 (another of those amazing coincidences of history), before Reagan Republicanism came to dominance. Although both might well have come to support Ronald Reagan, they were not at heart Reagan conservatives.
Neither, for example, would endorse Reagan’s assertion that “government is not the solution to our problem; government is the problem.” Storing, in particular, while capable of being critical of government, saw real conservatism to be not Jeffersonian minimalism about government but the alternative articulated in Federalist No. 51: “In framing a government which is to be administered by men over men, the great difficulty lies in this: you must first enable the government to control the governed; and in the next place, oblige it to control itself.” First, the power and ability to govern; next, the limits on that power.
Thus, Diamond and Storing were conservatives, but they were not the sort of conservatives that we have become used to. It is completely unimaginable to me that they could support President Trump or even Senator Ted Cruz, who made his mark by shutting down the government. They were, in the words Paul Carrese used to describe Storing in a recent article in American Political Thought, moderates in all ways. They did not favor large dramatic moves that would usher in either a liberal paradise or a conservative Eden. They opposed many positions associated with the absolutist free-speech doctrines pioneered by Justice Hugo Black; they also resisted the larger experiments in egalitarianism sponsored by the liberals in the 1960s and ’70s. But they never set up “the left” as agents of the devil, and sometimes even endorsed causes associated with the left.
They were, I suppose it is fair to say, neoconservatives. Certainly Diamond was, for he was often associated with thinkers of that tribe, and just as often highly praised by them. People like Daniel Patrick Moynihan and Jeane Kirkpatrick, stalwart neoconservatives, are on record with extravagant praise for Diamond’s work. In general, Diamond and Storing did not stand for anything radical or transformative. The president they were closest to was Gerald Ford — no utopian transformer of society. And they did not endorse one of the major planks of conservatism early and late: opposition to Big Government. Both of them, even the Madisonian Diamond, were actually devotees of Hamiltonianism, with its emphasis on big, powerful, and active national government.