This is the problem with geopolitical realism, especially when it is practiced with distain for domestic constraints. You begin with a reasonable-sounding worldliness, of the kind articulated by Metternich and quoted admiringly by Henry Kissinger: "Little given to abstract ideas, we accept things as they are and attempt to the the maximum not our ability to protect ourselves against delusions about reality." You then find yourself allying with disreputable foreign rulers on the 'realist' grounds that they are the people with whom you have to do business, forgetting that in doings you have deprived yourself of any political leverage over them, because the one thing that matters the most to them - how they get and keep power over their subjects - is of no interest to you. And at the last,you are thus reduced to cynicism about the outcomes not just of their actions but of your own.
Thus, as William Bundy pointed out in his book (The Tangled Web), some of the most vaunted achievements of 'realist' foreign policy turn out to be bogus. Kissinger and Nixon could hardly have been unaware, he concludes, that the Paris settlement of 1973 that 'ended' the Vietnam War was a mirage, its clauses and safeguards 'toothless.' It looked only to the short-term political advantage,with no vision or strategy for handling the longer-term fallout.Their unstinting support for the Shah of Iran was similarly disastrous- first joining him in misleading promises to the Kurds in order to bring pressure on Iran's western neighbor, Iraq, then abandoning those same Kurds to a bloody fate, and finally bonding the image and power of the U.S. to an increasingly indefensible regime in Tehran. Like so much else about the foreign dealings of the Nixon era- AND OUR OWN - the bill fell later: in 1975 in Vietnam and Cambodia,in 1979-80 in Iran. And in each case the interests of the United States were among the first victims.
This is the point: in a constitutionally ordered state where laws are derived from broad principles of right and wrong and where those principles are enshrined in a protected by agreed procedures and practices, it can never be in the long-term interests of the state or its citizens to flout those procedures at home or associate too closely with the enemies of your founding ideals.
The rhetoric of Gladstone's attacks on Disraeli in 1880 is dated,but his theme is unmistakable and familiar:
" Abroad the government the government has strained, if they have not endangered, the prerogative by gross misuse and have weakened the Empire by needless wars, unprofitable extensions and unwise engagements and have dishonored it in the eyes of Europe and the world. Disraeli's brazen unconcern for the behavior of its friends, or for the interests of others, especially small nations, are inimical to Britain's long-term interests. If British interests were accepted as 'the sole measure of right and wrong then the same logic might logically readopted by any other country, and the result would be international anarchy."