Over the next five months, the presidential campaigns are likely to be a demonstration of the worst side of American politics. The candidates expected to face each other—Donald Trump and Hillary Clinton—will be engaged in non-stop attacks on each other’s character, past, and personality, with less room for a real debate about real policy challenges and choices. The conflicting images of the two candidates in all too pervasive public opinion polls is a discouraging harbinger of how voters will be confronted with a barrage of negative ads and messages. And that is a bipartisan phenomenon. Many leading Republicans who were part of the “Never Trump” movement are now signed up as “Never Hillary” troops. The continuing battle between Clinton and primary opponent Bernie Sanders supporters has left a fracture within the Democratic Party which will not necessarily be bridged by the Clinton argument of “Never Trump.”

There may be many reasons why those who proclaim themselves as political experts have been unfailingly wrong about the success of Trump, Sanders, and the mood of the American voters in general. But there are few left—aside from their respective paid spokespersons—who will dare to predict the outcome of the November 8 elections. Meanwhile, as the rest of the world waits to see what will happen, there is ample reason for those watching this race unfold to be, as President Obama put it, “rattled” or nervous.

The unpredictability of a President Trump is self-evident in the impulsive, indeed contradictory, flow of his campaign rhetoric, particularly in the foreign policy realm. Given his lack of experience in elected office, there is simply no way to determine what he may do in dealing with the many global fires burning in several parts of the world. There is no foreign policy record to measure, no clear picture of those who would be in his administration serving and advising him, and no consistency in his views beyond general pronouncements.

In the case of Hillary Clinton, there is a far larger and longer record of foreign policy engagements and experience as First Lady, Senator, and Secretary of State. There is a clearer picture of those who she would likely include in her White House team. Certainly in most of the world’s capitals, Clinton is a known quantity.

But foreign policy expertise will not be the primary reason why either Trump or Clinton will win the election. Victory will be shaped by the capacity to mobilize voters more focused on domestic concerns—their jobs, their security, their futures and those of their children.  It will be shaped by who the majority of voters trust with those concerns. As of now, we cannot say with certainty who will be the most persuasive.

Eight years ago, if millions of Germans could have voted in the U.S. presidential election, the vast majority would have cast their ballot for Obama. Today, most would cast their votes against Donald Trump, if not with the same enthusiasm for Hillary Clinton as for Obama. Most Germans have understood that U.S. presidents are primarily focused on their own voters, that they are confronted and constrained by a Congress that sets limits on the White House. Presidents can and do lead U.S. foreign policy but they must also persuade Congress and the American public of the value of that policy. But it is clear now that there is a much weaker basis for a U.S. president to accomplish that primarily because a consensus around foreign policy priorities is no longer self-evident. And that is one of the primary reasons why the world—and particularly Europeans—should feel rattled.

The U.S. public is currently caught up in a fierce debate about how much American policy and its resources should be engaged in global conflicts; how much the U.S. can be the world’s policeman; how much the U.S. really benefits from alliances like NATO or trade negotiations like TTIP, preventing attacks on the Homeland, protecting individual privacy or the environment, strengthening the national economy and its infrastructure.  These are the questions for this campaign; whoever gives a more persuasive set of answers will be elected.

This is not going to be a pristine intellectual debate by any means. It is going to be hard fought and probably very ugly in parts. Much of it may shock or discourage non-Americans and diminish their expectations of the United States.

There is not a lot Germans or other Europeans can do to influence this debate. Yet how some Europeans answer these same questions about why various forms of partnership with the U.S. are not only in their interests, but also in the interests of the U.S. in meeting American concerns will be noticed.  Many of these challenges that Europeans and Americans share cannot be solved only in national frameworks. But unfortunately on both sides of the Atlantic there are increasing arguments that only a return to national sovereignty will offer a way out of these dilemmas. The debates in Europe are appearing just as ugly in their own backyards as the debate in the U.S.

In the end, whoever it is that American voters choose to send to the White House in January 2017—he or she—will face the challenge of re-forging a consensus around U.S. foreign policy priorities in light of both national needs and global realities. That same challenge faces every European leader today. The more that effort in finding solutions can be shared across the Atlantic—as it has been largely accomplished in the past several decades—the better chances for success. That will be in no small measure facilitated by a healthy, honest, and hopeful willingness to engage with each other. But that prospect is far less possible if the centrifugal forces on both sides of the Atlantic continue to gain traction.

Dr. Jackson Janes is the President of AICGS.