As First Year contributor Kyle Kondik argues in his essay, Scenario planning, the current state of polarized partisanship in American politics will likely be an important factor in the next president’s first year in office. Whether Donald Trump or Hillary Clinton win in November, and regardless of which party has a majority in the House or Senate, the next president is going to have to navigate a political system characterized by both parties’ refusal to cooperate with one another.

This current state of polarization—that is, the increased ideological difference between Democratic and Republican legislators—is partly strategic and partly rooted in a genuine lack of agreement on crucial issues. This polarization has major consequences for the next president’s ability to achieve legislative successes on two levels. First, the next president (much like President Obama) will face considerable hurdles in passing their legislative agenda through Congress. Second, the president (perhaps even more so than Obama) will also need to invest considerable energy in managing dissent from within their own party.

On the first point, the next president is most likely to face hurdles if the election produces another two years of divided government—that is, if the same party does not end up simultaneously holding the White House and majorities in House and Senate. In this scenario, the opposition party can easily block legislation. Since the party that lost the presidential election will want to limit the next president’s successes as much as possible, it is likely to attempt to block all but the most vital bills. While the next president can counteract this by focusing on issuing executive orders—much as Obama has done since the Republican takeover of the House in 2010—more ambitious plans that require legislation will have to be postponed.

To be sure, divided government itself does not mean government must be in a state of gridlock. Political scientists have concluded that, in a best case scenario presented by David Mayhew, divided government does not have to limit the likelihood of passing important pieces of legislation at all. Even more skeptical voices of this finding, such as Sarah Binder, still conclude that while divided government does correlate with legislative gridlock, its cause is more inherent to the design of House and Senate than anything else.

Indeed, we do not have to go back far in time to identify major laws passed with bipartisan majorities. For example, No Child Left Behind—a major accomplishment during George W. Bush’s first two years in office—was passed with support from Republicans as well as Democrats such as Ted Kennedy. During the presidency of Bill Clinton, meanwhile, Republicans and Democrats were forced to cooperate after the GOP takeover of House and Senate in the 1994 midterms. They worked together on issues such as welfare reform. But in recent years, such bipartisanship has become increasingly rare.

However, polarization is not merely a problem under divided government. Even in a case of unified federal government—which, as Kondik argues, is most likely in the case of a Trump victory—polarization will provide constraints. While in the House, the majority party can pass the legislation it prefers, minority parties in the Senate generally have considerable options to slow down the legislative process and even prevent bills from being brought to a vote.

Since it appears unlikely either party will be able to get a supermajority in the Senate, major new bills will require cooperation between the minority and majority party. This constraint is considerable: the Affordable Care Act (commonly referred to as Obamacare) was passed under unified Democratic control of government without a single Republican vote in support but was nearly derailed when Democrats lost their supermajority in the Senate.

Crucially, polarization also affects intra-party politics. Coordination with the other party will require the next president to make compromises and sell those to her/his own party. There is a good chance that the 2016 election will make this process harder too. As political scientists Gary W. Cox and Mathew D. McCubbins have shown, parties in Congress generally rely on majority rule within their caucus. The process of polarization not only has resulted in both parties drifting further away from one another, it also has placed the more extreme factions of the parties in the majority position within their caucus.

The result has been that the conservative wing of the GOP has been particularly successful in blocking attempts by the party’s (slightly) more moderate leaders to compromise with the Obama administration. It is unlikely that this wing of the party will disappear or greatly change its tune with the 2016 election. Additionally, President Trump would also face hostility from a considerable number of Republican members of the House and Senate who he has alienated during his peculiar election campaign. A Trump victory might bridge some of these divides, but it is not unthinkable that Republicans in Congress will not be particularly loyal to their new president.

Until now, much of the intra-party effects of polarization have been a Republican ‘Tea Party’ problem. But the 2016 campaign has shown that the Democratic Party is not unified either. Indeed, Bernie Sanders’ successful primary run indicates that there is a considerable distance between many Democratic Party leaders and part of the Democratic voting base. It is not unthinkable that this could result in members of the Democratic Party in Congress also moving to the left out of fear of progressive primary challenges in 2018. If so, President Clinton would need to navigate between compromising with Republicans while also keeping the more liberal Sanders wing of the party happy.

Thus the first year in office of President Trump or President Clinton will require a delicate hand at managing relations with the other party as well as their own. Even in the case of unified government—by far the easiest outcome in terms of preventing legislative gridlock—this will be a hard task. If the election produces divided government, it seems likely that the next president will find themselves in a very similar situation as President Obama has found himself: unable to win major legislative successes and forced to rely increasingly on powers inherent to the executive branch to achieve policy outcomes.

Boris Heersink is a PhD candidate at the Department of Politics at the University of Virginia and a former fellow at the Miller Center. His research focuses on political parties, elections, and Southern politics.