You might think that securing the White House, Senate, House of Representatives and a majority of seats on the Supreme Court would enable a party to practically dictate laws and policy. But so far, unified government hasn’t worked out too well for Republicans. The GOP has controlled both houses of Congress and the presidency since January but has no major legislative accomplishments to show for it. President Trump finally managed to close a big deal last week, to stave off a government shutdown and Treasury default for the next three months and secure hurricane disaster relief. And yet he cut the deal with Democrats — against the wishes of GOP leaders.

One thing the Republicans have done, however, is demonstrate that controlling government isn’t enough to govern. Since the U.S. system is designed to slow down and complicate attempts at change, even parties in control of the whole government have to learn how to navigate it. What makes that so hard? There are several things that a majority party needs in order to convert political victories into legislative ones, and the GOP doesn’t have them.

This one seems obvious but can be deceptively difficult. Research shows that agenda control is a key source of power for the majority party in Congress. For a party to effectively implement an agenda, it has to (i) agree on what that agenda is, and (ii) how that agenda should be prioritized. The first part isn’t a given; Republicans largely support lower taxes, for instance, but — as the recent healthcare debate showed — they are less unified on health care policy.

Even when there’s agreement on the issues, parties must also decide on which ones to focus. Democrats, for example, controlled the White House, Senate and House in the post-New Deal era, through most of Harry Truman’s presidency, from 1961 through 1969 under John F. Kennedy and Lyndon Johnson, and again from 1977 to 1981 when Jimmy Carter was in office. During this time, they had to decide what policy goals to prioritize: economic reforms, health care coverage, arts and education, rural development, urban revitalization, civil rights? Some leaders, like Johnson, were able to tie many domestic issues together, while others, like Carter, came off as unfocused. Health care reform wasn’t prioritized and it remained on the Democratic to-do list all the way to the presidencies of Bill Clinton and Barack Obama.

https://fivethirtyeight.com/features/why-republicans-cant-govern/