Broadly, a mandate is the authority that voters confer on an elected official to act as their representative. Usually, though, a political mandate, or “popular mandate,” refers to the idea that a political official has been elected because the public strongly supports their platforms and wants to see them enacted.
After Franklin Delano Roosevelt won his re-election by a landslide, he felt confident that the American people had given him a mandate to expand his New Deal policies. Whitehouse.gov explains that there was a tension between what businessmen and bankers wanted, on the one hand, and what Roosevelt believed that his supporters wanted, on the other hand:
By 1935 the Nation had achieved some measure of recovery, but businessmen and bankers were turning more and more against Roosevelt’s New Deal program. They feared his experiments, were appalled because he had taken the Nation off the gold standard and allowed deficits in the budget, and disliked the concessions to labor. Roosevelt responded with a new program of reform: Social Security, heavier taxes on the wealthy, new controls over banks and public utilities, and an enormous work relief program for the unemployed.
In 1936 he was re-elected by a top-heavy margin. Feeling he was armed with a popular mandate, he sought legislation to enlarge the Supreme Court, which had been invalidating key New Deal measures. Roosevelt lost the Supreme Court battle, but a revolution in constitutional law took place. Thereafter the Government could legally regulate the economy.
In modern times, virtually every president claims to have been elected by a powerful mandate – no matter how close the actual election was. And, with every election, the press assesses the size of the new president’s mandate. When Obama won re-election in 2012, for example, NPR ran a piece titled “For Obama, Vindication, but not a Mandate.” The piece acknowledged that Obama felt differently about his own victory and believed himself to have a mandate:
Despite the close result in the popular vote nationwide, Obama wasted no time claiming vindication for his ideas. In his victory speech early Wednesday in Chicago, he tied his re-election to two centuries of American progress.
Just a few years later, Donald Trump’s election staggered the media and led to a rash of articles debating whether the new president had a mandate. For some, the mandate was clear; as AP reported, then- House Speaker Paul Ryan called Trump’s victory “a repudiation of the status quo of failed liberal progressive policies.” Critics, however, argued that Trump did not have a mandate because he had won the electoral college but had failed to win the popular vote.
Sometimes, though, a mandate can be conferred long after a president is already elected. In 2002, the Atlantic ran a piece arguing that President George Bush had finally won his mandate two years into his term. Bush made the midterm congressional elections a referendum on his presidency, and Republicans swept Congress in that election:
President Bush has finally won his mandate, the one he failed to get two years ago.
Presidents are supposed to have coattails when they get elected, not in a midterm election. Midterms are when presidents are supposed to see their parties suffer setbacks in Congress. That’s been the rule in virtually every midterm since the Civil War.