I've been impressed by the wide range of reactions to Donald Trump's election. Some folks are so dejected that they've entered a news-free zone to recover and to brace themselves for what they expect will be wholesale devastation of all they care about. Others are flying high over Trump's unexpected triumph, gleefully anticipating his revolution and his promised draining of the Washington swamp with its slithering special interests and dimwitted bureaucrats.

Maybe you fit into one of these overheated groups or — like many — are just uncertain about what to expect from President Trump. What are realistic expectations for the first 100 days — a traditional marker for any new administration?

Sit down.

Trump will score some big wins soon after his inauguration. Tax cuts and possibly the repeal of Obamacare will be passed by Congress, and signed. He'll also issue a stream of executive orders to reverse President Obama's policies — limiting immigration, approving fossil-fuel drilling and pipeline projects, approving interrogations that independent observers consider torture, and more. And despite his seemingly conciliatory comments about global climate change, Trump can readily reverse course.

On foreign policy and national security, the Trump administration is likely to reverse or recast longstanding policies and implement new ones. The bipartisan push by successive presidents to lower trade barriers appears to be in Trump's sights as he prepares to slap a tariff on imports. NATO may also be in for a shakeup as the foundation of America's partnership with Europe in confronting the Soviet Union years ago and now resisting Russian aggression in Crimea and Yugoslavia.

Elections matter, and that will soon be obvious.

You may be justifiably wondering: "Why don't you tell me something I didn't know?" Trump supporters may feel vindicated at Trump's prospects for reversing Obama's legacy and that of previous Democrats. From those in self-imposed exile, I hear the scornful response — "I knew things would be this bad."

But here is where Trump will meet a phalanx of resisters and a border wall of checks on presidential power that founding father James Madison erected.

Let's trade the euphoria about wholesale transformation — and the fatalism over uniform devastation — for realism about how American governing works. A realist's guide to Trump's first 100 days flags five obstacles that may stymie the new administration:

1. Too much talking — and tweeting

Trump's eagerness for public attention works well in the development business and show business, and in winning elections, but not when governing. Ronald Reagan was the "Teflon president" because he restricted his public comments and allowed his cabinet secretaries and senior officials to become the lightning rods. David Stockman served as the face of his budget cuts; James Watt was the frontman for his controversial promotion of federal land development.

Presidents skilled in exercising power expect mishaps and resistance and avoid putting their political capital on the line unnecessarily. Dwight Eisenhower is lauded today for serving as a "hidden hand president." The public saw him on the golf course and blamed others for trouble — while the president worked his will behind the scenes.

Prediction: Trump's stream of slashing tweets and public statements will tire many Americans who may reward him with low approval ratings early in his term.

2. Political self-interest rules — and varies

Republicans will get much done because they control both chambers of Congress and the White House. And yet, the coin of the realm in Washington remains self-interest. Republicans in the House generally come from ideologically homogenous districts — for them, being quite conservative is smart politics (as is being liberal for members from progressive districts). But a number of GOP senators represent more politically divided states and know that going too far in one direction can put them at risk in the next election.

Exhibit A: Repealing the Affordable Care Act is popular among conservatives, who dominate GOP House districts. But it is supported by only a quarter of Americans overall, with the majority favoring more modest or liberal options. It makes political sense for archconservatives in the House to push for repeal by holding out the dubious promise that the GOP House — including its rabid Tea Party faction — will sign onto a feasible replacement in the future. But pragmatic conservatives in the Senate have been to this rodeo before and witnessed the House Freedom Caucus deep-six solid conservative legislation that didn't satisfy its standards of purity.

Prediction: Senate Republicans may be reluctant to vote for archconservative legislation. Defections by three will be enough to defeat bills if Democrats remain unified.

3. Washington's tangled chain of command

Trump mistakenly assumes he can govern based on his experience as a CEO whose commands were followed down the corporate ladder. He is using his vice president as a kind of chief operating officer and his top White House appointees — Reince Priebus and Steve Bannon — as senior vice presidents. He is filling many senior cabinet posts with heads of large businesses (and generals) who are familiar with rigid hierarchy.

Big problem — presidents cannot establish a chain of command.

The Constitution grants authority to Congress as a coequal branch of government. In the enduring tug-of-war between Congress and the president, the legislative branch indisputably holds the upper hand when it comes to the power of the purse. Congress uses its control over the appropriation of money not only to redirect the wishes of presidents (even those who are from the same party) but also to discipline departments and agencies. Executive offices that defy Congress find their budgets and programs slashed. In the gory lexicon inside the Washington beltway, they are left bloody — a gruesome warning to others.

As it has for generations, the new Congress will use its control over money to insist on shared control over departments and agencies — and it will often win. Trump will come to learn that his dependence on Congress for approval of funding becomes a source of legislative power, reordering his priorities and checking his efforts to rule over the sprawling executive branch.

Prediction: Trump's plans to eliminate or slash weapons systems will be reversed by Congress when it writes the budget. Weapons systems are intended to defend America, but they also provide jobs. Legislators representing the districts where Trump's targeted weapons systems are built will use their power of the purse to sustain those systems.

Here's the kicker — in matters like these, Republicans will be among Trump's foes.

4. The president as clerk

Here's another obstacle Trump will discover: The department and agency careerists candidate Trump mocked as "stupid" are, in reality, quite cunning. Veterans of Washington politics appreciate that agencies are often run by skilled and resourceful leaders who use a familiar tool kit to evade presidential directives and pursue their own agendas. If Trump isn't careful, he may unwittingly become a clerk filling the budget requests of the bureaucracy he underestimated.

Wait a minute — how can a president be outmaneuvered by bureaucrats?

One trick is to leak damaging stories to the press — a maneuver we are now witnessing in the Energy and State departments as officials push back on Trump's transition team. Later, Trump will witness skillful agency heads play the White House off against Congress to gain leeway. Then, there will be the Benedict Arnold collaborations with interest groups and advocates — some of whom may go to court to challenge Trump directives.

After getting the runaround by agencies, Trump may start to think back nostalgically to his ability on "The Apprentice" to shout out — "You're fired." If he does try to fire what he considers insubordinates, he'll find himself handcuffed by the administrative rules and political alliances that protect many civil servants.

And, that's not the sharpest disappointment awaiting Trump. His own staff in the White House may set up shop on their own — inserting their priorities in place of the president's. Example: Vice President Dick Cheney's power grab under George W. Bush.

Prediction: Vice President Mike Pence may outdo Cheney in his ability to manipulate an inexperienced first-term president to advance his own agenda.

5. Press relations are symbiotic — or problematic

Trump understandably takes credit for the healthy profit margins at CNN and other media businesses that showered him with free coverage during 2016. Granting access to journalists covering the White House, he seems to have concluded, is a favor to them.

But the reverse is also true. Generations of presidents have granted wide access to the press because of hard-nosed realism about their own political interests. For more than a century, the White House has supplied the press with access to senior officials and coveted background information to create — as a senior White House official once told me — a "controlled flow of information."

Prediction: If the Trump White House sticks with its initial inclination to restrict access, it will turn loose enterprising reporters to shine a light on personal embarrassments (did I hear someone say "conflict of interest"?) or failing administration policies. Trump would do himself a favor by engaging the press as much as he can — not by ignoring or mocking it.

• • •

Strap in. We are heading for a rocky ride. Trump will secure impressive wins but he may also needlessly squander his political capital and miss opportunities.

My advice: Both the supporters and opponents of Trump should sit up and pay attention. Realism — not exaggerated rhetoric — is the most reliable compass for the years ahead.

Lawrence R. Jacobs is Mondale Chair at the University of Minnesota. He has researched and taught the American presidency and executive politics for nearly three decades.