President Trump promised to repeal and replace the Affordable Care Act "immediately" and "on Day 1" while on the campaign trail. But now, he claims he never said he'd get health care reform done quickly. (Peter Stevenson/The Washington Post)

The decision to pull the American Health Care Act (AHCA) from the House floor on Friday is a telling reminder of the limits of presidential power when it comes to leading the legislature. Our separated system makes it hard for presidents to translate their preferences into policy, even on priority matters. As Lyndon Johnson put it, complaining about the Kennedy staff’s inability to get bills moving: “You can’t start yelling ‘frog’ at everybody and expect ‘em to jump!”

A quick review of political science literature on presidential success in Congress gives us several lenses through which to view Friday’s happenings. One consistent finding is that presidential personality — and the schmoozing of legislators, etc. — matters mostly “at the margins,” as George Edwards put it. In a close vote, those margins surely might matter. But systematic factors were also at play:

1) Context matters.

In times of crisis, legislators are more likely to defer to presidential initiative as they “rally ’round the flag.” But despite the president’s rhetoric painting the Affordable Care Act (ACA) as a “disaster” requiring emergency attention, one key factor driving immediate action seemed to be far more mundane: the desire to do so using a spring reconciliation bill not subject to Senate filibuster, so that the reconciliation process could be used again later this year to make sure a tax reform/cuts bill also avoided filibuster. (The ability to write two reconciliation bills in the same calendar year, for two different fiscal years, is a convenient by-product of Congress having done so little work in 2016.)

The 2016 election results could be read as a mandate for the long-standing GOP promise to repeal the ACA, which President Trump fully endorsed, saying he would even call a special session of Congress to do so. But polling showing increasing support for the ACA suggested the matter was rather murkier than this.

It also reminds us of the evergreen truth that people like benefits, once they have them; the case for taking those benefits away is difficult for legislators to make. This bill, unlike past efforts to repeal the ACA, was not “fantasy football.”

2) Parties matter, but …

Victorian-era British prime minister Benjamin Disraeli’s aphorism, “A majority is the best repartee,” captures a basic truth about presidential success in Congress: size (of one’s party) matters. The number of seats the president’s party holds, Paul Light notes, is the “gold standard” of likely legislative success. Lyndon Johnson’s famous “treatment” — the way he lobbied members of Congress in person and by phone — was a lot more effective before the disastrous 1966 midterms than after.

By this standard, President Trump started the repeal process in great shape, given the largest Republican majority in the House since the late 1920s and 52 Senate seats. But if partisanship is strong, the organized parties may not be. While the GOP is surely both more homogeneous and more conservative than it used to be, divisions within its factions were on clear display during the brief life of this iteration of health-care reform. Moving to the left upset the conservative Freedom Caucus; moving to the right upset the moderate Tuesday Club; and the Senate’s divides were perhaps even wider.

President Trump complained Friday that “We had great support among most Republicans but no Democratic votes, zero, not one.” But the bill was not written with any Democratic input (or votes in mind), making the balancing act even more difficult.

3) Agenda setting matters.

That in turn made the specifics of the bill even more important. The outcomes of any collective decision are strongly dependent on the alternatives that are on the table: bargaining starts with agenda-setting and policy formulation. But this, in turn, requires a deep dive into policy details — in this case, of a notoriously complex issue. The president never showed much knowledge of, or interest in, what the bill actually did. Yet members of Congress — granted, in diametrically opposed ways — objected to it based on its substance as well as its symbolism.

4) Presidential resources matter.

In his famous book Presidential Power, Richard E. Neustadt argued that a president’s ability to persuade rested on three legs: their reputation for “skill and will,” their public prestige, and their formal powers. None of these were particularly in Trump’s favor in this case.

Reputation, Neustadt suggested, means that presidents must concern themselves with what others think of them. Will the president stick to a given position? Does he know how to shift the levers of government? President Trump’s positions on health-care policy varied wildly across the course of the campaign and transition period, making it hard to know what aspects of the bill he would stick to and which would soon be attacked on Twitter.

Neustadt didn’t see prestige — as roughly measured by presidential approval — as a fungible asset (“let’s trade 3 percent of our popularity for this vote!”) But he did think an incumbent’s broad range of approval might matter as a “bank shot,” coming back from specific elements of the public to have an effect on key Washingtonians.

Trump’s overall approval rating is quite poor relative to his predecessors’ standing at this point in their terms — Gallup’s daily tracking poll had Trump at 41 percent on Thursday, while RCP’s average of polls is at 42.7 percent. And, as Sarah Binder has pointed out, Trump ran behind 90 percent of Republican members of Congress in their districts in 2016. While those districts almost certainly have a better opinion of the president than those with Democratic representatives, they probably like and trust their member of Congress even more.

Formal powers are less useful as they cross the separation of powers. True, in the legislative setting the veto power can be critical, as key leverage over the substance of a bill. But there was little question of any version of the AHCA being vetoed. And the kind of carrot often associated with presidential persuasion in the past – “how about a nice dam for your district?” — runs up against both the GOP’s earmark ban and Trump’s own budget plans for domestic discretionary spending.

In short, presidents can’t order members of Congress to do things. Harry Truman reportedly said that “I sit here all day trying to persuade people to do the things they ought to have sense enough to do without my persuading them. That’s all the powers of the President amount to.” If that’s not the whole story, it’s far truer when dealing with Congress than in the wider world of presidential authority.