The U.S. political class and political system in effect grant a lot of leeway and a lot of tolerance to excesses of American politicians, including excesses exhibited during election campaigns. There is little consistency and almost no principle in determining which comments by candidates come to be considered as campaign-crippling gaffes and which do not. Much gets said that does not cripple a campaign but which a majority of decent Americans, if they carefully thought about it, would probably agree is unreasonable, untrue, mean, inflammatory, bigoted, or extreme.

The tolerance comes partly from an acceptance that, oh well, politicians will be politicians, and that especially during a race for a party's nomination extreme things will be said to appeal to the angriest and most active part of a party's base and will not necessarily endure during a general election campaign let alone once the winner takes office. It comes partly from a quest for even-handedness, especially among the press, involving a supposed need to give equal respect to every position expressed merely because it is expressed, regardless of the unreasonableness of its content. And it comes partly from how much all of us who are political junkies (which includes to varying degrees a large proportion of the U.S. population) are entertained by the spectacle. This last factor has been especially at work this year with the phenomenon that is Donald Trump, who first came to be known to most Americans primarily as an entertainer. What is extreme and unreasonable gets treated as harmless fun.

Essays can and should be written on how the fun isn't really harmless even when confining our perspective to the United States—about how this sort of crude followership rather than the exercise of true leadership by contenders in political races is a race to the bottom when it comes to reason and decency, and how it encourages a further lowering of political and moral standards among the America public as a whole and not just in the portions of the electorate that are the main targets of the crude appeals. But what may be even more likely to be overlooked is the effect such discourse has on perceptions overseas.

American politics unfortunately has not been stopping at the water's edge, in at least a couple of respects. One, which we saw recently with opposition to the nuclear agreement with Iran, involves how much domestic politics complicates and impedes the making and implementation of U.S. foreign policy. Another involves foreign governments and publics forming impressions about the United States and about Americans based on what they see and hear going on in American politics, including the crazy and disgusting aspects of it. Globalization and modern mass communications have made this second factor more important and more inescapable than ever.

Every indication of dysfunction in U.S. politics diminishes in foreign eyes the reliability and trustworthiness of the United States as a partner and leader in world affairs. Foreigners just got another such indication with the resignation of the speaker of the House of Representatives because members of his own party considered him insufficiently obdurate and too willing to work cooperatively with others.

Beyond the general picture of dysfunction are more specific hateful or prejudicial positions that some politicians get away with taking, which leads foreigners to conclude reasonably that such views must be shared by much and even most of the American public. This greatly harms the image of America as an open and tolerant land and the substantial soft power that has flowed from it.

The problem has been most acute in recent years, though by no means limited to, the frequent indications of Islamophobia. It is bad enough when impressions are conveyed to foreigners by the words and actions of Koran-burning pastors or religiously biased army generals. It has become even worse with leading (according to opinion polls) candidates for the presidential nomination of one of the two major U.S. political parties appearing to go along with statements that “We have a problem in this country—it's called Muslims” or stating themselves (notwithstanding Article VI of the U.S. Constitution) that a Muslim should never be president of the United States.

The deleterious effects in majority Muslim countries of such postures taken by U.S. politicians are multiple. The belief that the United States as a whole is out to persecute or subjugate Muslims gets entrenched, making it that much harder for the United States to win trust and get accomplished what it wants to accomplish in those parts of the world. Foreign governments, sensitive to their own public opinion, find it politically harder to cooperate with the United States. The motivations for anti-U.S. extremist violence grow stronger, and thus the probability of such violence increases.

Politicians who like to appeal to the baser sentiments of a political base ought to think hard about such consequences. If they nonetheless continue such appeals, they ought to be condemned for doing so and voters ought to reject them, decisively.