How powerful is the most powerful person in the world? As powerful as we make him

One of the sentiments I've heard most often in the days following the election is that people feel largely powerless to stop Donald Trump and the Republican Party from carrying out their vision (repealing Obamacare, building walls, deporting millions of immigrants, pulling out of climate deals, blocking common-sense gun regulations).
Don't be so sure.
It's easy to forget how powerless the most powerful man in the world can quickly become when he lacks public support and approval for his agenda. It's one of the brilliant aspects of the checks-and-balances systems the forefathers enshrined in our Constitution.

George W. Bush's approval ratings as president

Be careful what you wish for

A little history. The success of presidents whose party controls Congress in carrying out their agenda has been largely checkered, particularly in modern times. Jimmy Carter's party controlled both houses of Congress for all four years of his presidency, and he had among the worst relationships with Congress of any modern president, accomplishing little. Bill Clinton's party controlled Congress the first two years of his presidency, and his (and Hillary's) health care plan went up in smoke, before the Republican Revolution of 1994 that left him to argue he was still relevant (remember "the Constitution makes me relevant"). George W. Bush famously said after the 2004 election that he was going to use the "political capital" from his re-election to push the privatization of Social Security through a Republican-controlled Congress. It went nowhere, and two years later the Democrats seized control of both houses, laying the foundation for Barack Obama's rise two years after that. Even Obama nearly failed to pass the Affordable Care Act, succeeding by only the slimmest of margins when he lost his filibuster-proof Senate, before his lukewarm approval numbers cost the Democrats the House in 2010 and the Senate in 2014..

Power from the people

Why have so many presidents failed when they seemingly had free rein to push their legislative program through a friendly Congress? It all comes down to popularity and approval ratings. Carter, Clinton, Bush and even Obama all suffered from lackluster approval ratings when their party controlled Congress, and that cost them the "capital" they needed to deliver on their plans. Every member of Congress is thinking about the next election, or that of their successor. When the president is popular with the American people, regardless of party, they are likely to go along with large parts of his agenda (think Ronald Reagan's tax cuts). When he is not, regardless of party, they are likely to run for the hills.
What Donald Trump is, or is not, able to do over the next four years will largely depend on his popularity with you and me. Given where he stands now, he has Mt. Everest to climb.