Let an election go on long enough, and the press is bound to work its way around to covering a candidate’s “mandate” before she’s even elected. The term, which refers to the alchemy of an electorate’s votes transforming into legislation, has been a mainstay in media coverage of Hillary Clinton’s potential presidency. The Los Angeles Times warned, “By focusing on the other guy’s flaws, Clinton may fail to build a strong mandate for her agenda.” The New Yorker’s Ryan Lizza wrote about “Clinton’s mandate problem,” while The New York Times’ Frank Bruni referred in a column to her “resounding mandate.” All of these stories wrestle with a central question, one that’s even more salient in these final days as polls narrow and Clinton’s potential victory is in more doubt: Will the early days of Clinton or Trump’s presidency be different if she or he barely wins?

One of the main ideas behind mandates is that some elections are exceptional, carrying an urgent message from the electorate that confers special authority on the president or other elected officials. And sure enough, political science research suggests that, yes, mandates can shape which policies Congress enacts. But figuring out when a mandate exists is a separate issue, in part because election results are often ambiguous. Take the 1980 election, for example: Ronald Reagan beat Jimmy Carter by nearly 10 points and won over 90 percent of the Electoral College votes, while Republicans made significant congressional gains. But as political scientist Robert Dahl (and musician Gil-Scott Heron) pointed out, Reagan won less than 51 percent of the popular votes cast. Yet Reagan wasn’t shy about claiming a mandate for his new conservative agenda.

Then, of course, there’s the issue of who decides that a mandate exists. Most of the contemporary research finds that what matters most in establishing a mandate is the story that comes afterward, not what candidates say during the campaign. However, there’s less agreement among scholars about who shapes that narrative — media or politicians.

And then, finally, one has to suss out what kind of mandate a president has. There are different types: Observers can determine that the contest was a personal mandate for the candidate, a policy mandate for a specific aspect of the candidate’s agenda, or a party mandate for the party platform and governing approach, and there’s some evidence that it can be easier for presidents to define a mandate for change than for the status quo.

Despite all this subjectivity, Congress’s behavior does seem to shift when there’s lots of mandate talk in the air. Political scientists Lawrence Grossback, David Peterson and James Stimson found that members of Congress responded to media cues that a mandate election had occurred, deviating from their usual voting habits for a few months at most. Surprise, these scholars argue, is the key element in the development of mandate narratives in the media. The elections of 1964 (for the effect of the presidential race on Congress), 1980 and 1994, for example, took observers by surprise and required explanation. The explanation offered by media observers was that voters had been clear in their desire for party’s agenda to be enacted. The media interpretations of the election after the fact created a convincing story about the policy meaning of the election.

Can presidents themselves convince Congress that an election carried with it a mandate? I’ve looked into this issue with David Peterson, an Iowa State University professor and co-author of the research mentioned above, and we found that when presidents identify the election as a mandate, members of Congress respond. Our study covered presidents from John F. Kennedy through Barack Obama, and drew on the research that I did on how presidents interpret election results in their rhetoric. Looking at a wide range of presidential remarks, I assessed whether each communication event used the election results to justify what the president was doing. I found that presidents interpret elections in a variety of ways: sometimes as mandates for their own leadership and judgment, but more often for the issues and governing philosophies they talked about during the campaign. Contrary to what we might expect, the final vote shares don’t seem to matter.

Despite the challenges of determining the meaning of an election, leaders have grown increasingly fond of claiming them. In my study of presidential mandate claims, I found substantial change over time. President Franklin Roosevelt rarely invoked the election result when he was presenting early New Deal ideas in 1933, but more recent presidents such as Bill Clinton and George W. Bush have frequently invoked the election to justify their policy ideas, big and small. The major turning point appears to have been the Nixon and Carter administrations, neither of which tend to come to mind when we think of major presidential mandates. Documents from these administrations reveal that references to election results were less about the results themselves and more about the need for presidents to justify their leadership in an increasingly hostile political environment. Party polarization had begun, trust in institutions had declined, and as a result, the presidency no longer commanded the respect it once did. In other words, reaching for rhetoric about “doing what I was elected to do” or “fulfilling the promises of my campaign” has become a standard way of defending presidential legitimacy in general.

PRESIDENT YEAR ELECTORAL COLLEGE VOTE SHARE POPULAR VOTE MARGIN OVER CLOSEST OPPONENT SHARE OF PRESIDENTIAL COMMUNICATIONS WITH MANDATE CLAIMS Obama 2012 61.7% +3.9 3.6% 2008 67.8 +7.2 18.1 G.W. Bush 2004 53.2 +2.4 28.7 2000 50.4 -0.5 3.6 Clinton 1996 70.4 +8.5 0.7 1992 68.8 +5.6 8.9 G.H.W. Bush 1988 79.2 +7.8 14.1 Reagan 1984 97.6 +18.2 8.3 1980 90.9 +9.7 10.1 Carter 1976 55.2 +2.1 8.6 Nixon 1972 96.7 +23.2 8.1 1968 55.9 +0.7 5.9 Johnson 1964 90.3 +22.6 2.1 Kennedy 1960 56.4 +0.2 0.0 Eisenhower 1956 86.1 +15.4 3.8 1952 83.2 +10.5 12.5 Truman 1948 57.1 +4.4 5.3 F.D. Roosevelt 1944 81.4 +7.5 0.0 1940 84.6 +9.9 0.0 1936 98.5 +24.3 8.7 1932* 88.9 +17.8 3.1 Hoover 1928* 83.6 +17.4 10.6 Post-inauguration presidential mandate claims * For Herbert Hoover’s term and FDR’s first term, the dataset includes communications from the inauguration date on March 4 through the end of June. For presidents inaugurated in 1937 and afterward, the dataset includes communications from Jan.

20 through the end of March Source: American Presidency Project

Of course, mandates don’t always result in legislative action, even when a mandate is claimed. Obama’s success with the Affordable Care Act, for example, was most likely due to Democratic majorities in Congress, not his election victory. (In fact, my research with Justin Vaughn shows that health care was not prominent among the issues that Obama linked to the election result.)

What does all of this mean for a possible President Hillary Clinton? Regardless of what the election results look like, she’ll probably face fierce opposition and be on the defensive fairly often. That suggests that, like her recent predecessors, she’ll use quite a bit of mandate rhetoric. And that could influence some members of Congress, making it a bit easier for her main priorities to become law. It’s not likely that the media will develop a mandate narrative to explain her success, given that a victory – even a landslide — for the historic Democratic candidate is expected. But Clinton may also have some room to define the early politics of her administration and convey her own narrative of the election to legislators.

In the less likely event of a President Donald Trump … well, rhetorical predictions are that much harder to make. But such a victory would certainly fit the “surprise” criterion, possibly sending the media scrambling for an explanation.