The American dream of a stable and prosperous middle-class life—even for those who don’t go to college—has been slipping away, but Trump’s election would change all of that, at least in the minds of his supporters. Hope has returned to the heartland, and expectations couldn’t be higher. This time, hope and change will be more than rhetorical.

Obligingly, the stock market has confirmed that happy days are here again. On November 4th, the Dow closed at 17,888. In the last few days, it has tantalizingly hovered near the 20,000 benchmark, having risen roughly 9% since the election. Trump hasn’t even taken the Oath of Office, and Carrier Corporation has partially reversed plans to move manufacturing at a facility in Indiana to Mexico; Fiat Chrysler (FCAU) has announced plans to invest $1 billion in two U.S. plants; and Trump met with Alibaba (BABA) founder and executive chairman Jack Ma to discuss that company’s plans to create 1 million new jobs in the U.S.

The prospects for accelerated economic growth under a Trump administration are certainly plausible—pro-growth tax reform and reduced regulatory burdens should create a propitious environment for investment and job creation. Nevertheless, globalization and manufacturing automation, two powerful trends that have eroded the economic prosperity of the American working class, are here to stay. Slowing the pace of these changes and finding ways to ease the transition to a new economy would be impressive accomplishments for the president-elect, but a return to the economic dominance and prosperity that Americans enjoyed in the 1950s is not in the cards.

Trump’s ability to mobilize his voters in support of a pro-growth agenda will depend on his ability to keep their expectations in check. Unrealistic expectations, fueled by the Trump team’s emphasis on how quickly things will change, will inevitably lead to disenchantment and disengagement. If Trump’s support weakens, the American political system will provide ample opportunity for opponents to obstruct the president’s agenda.

Trump is not the first president to confront this dilemma. Barack Obama won in 2008 after promising a post-racial and post-partisan presidency. But as he noted in his farewell address last week, the expectations for a post-racial presidency were “never realistic.” And, given the enactment of the Affordable Care Act without a single Republican vote, it’s safe to say that the post-partisan promise was equally unrealistic. To his credit, Obama recognized the threat that unrealistic expectations posed to his presidency even before he took office, and during his first Inaugural Address, he reminded his supporters that “the challenges we face are real,” and noted that they “will not be met easily or in a short span of time.”

Trump’s inaugural address should emphasize that the challenges we face, both domestic and foreign, do not have simple solutions. While he must give Americans hope that we can grow our economy and enhance our security, he should prepare us for a long and difficult road. A toned-down version of Winston Churchill’s “I have nothing to offer but blood, toil, tears, and sweat” would be just the ticket. Trump supporters don’t expect miracles, as many of them had reservations about him to begin with. They were aware that he lacks political experience and they expect him to make mistakes. His campaign for the presidency was replete with self-inflicted wounds, yet, defying the expectations of all pundits, Trump still prevailed.

Working-class Americans embraced Trump because he gave voice to their concerns and, if he uses his inaugural address to prepare them to expect setbacks, they will stay the course when the world doesn’t change overnight.

Donald Brand is a professor of political science at the College of the Holy Cross.