Republican members of Congress listen as Barack Obama delivers the State of the Union Address.Pablo Martinez Monsivais / AP

There is a fundamental conflict at the heart of the Constitution that is bedeviling current Republican efforts to retake the White House: The president and Congress don’t have to be controlled by the same political party. In fact, the need for Republicans to keep control of Congress may be an obstacle the party’s presidential nominee cannot overcome.

Former Republican House Majority Leader Eric Cantor has complained that his party has been very unrealistic in its expectations of what it could accomplish, legislatively, with just control of Congress, given the president’s veto power. Overriding a veto would require a larger majority than Republicans have in either the House of Representatives or Senate, even without the filibuster.

For the past five years, the Republicans’ strategy appears to have been to back the president into a corner when must-pass legislation comes up. They have repeatedly threatened to default on the national debt and shut down the entire government to get their way. But even many Republicans in Congress have balked at such nuclear options, and anyway it hasn’t worked: They have failed to achieve cherished Republican goals, such as repealing the Affordable Care Act.

Nevertheless, control of Congress is extremely valuable to certain Republican constituencies even without the White House. The ideologically committed are satisfied that a Republican Congress at least keeps President Obama from doing further harm to the country and that incremental progress has been achieved in some areas, such as reducing the federal budget deficit. Moreover, lobbyists are often successful in getting their way on appropriations bills, where the composition of spending is as important as the amount. Indeed, from the point of view of most lobbyists, control of Congress is far more valuable than control of the White House.

This wasn’t always the case. Before the Budget Act of 1974, the administration’s hand was much stronger and getting a spending priority into the president’s budget was essential to enactment. The president also had de facto line-item veto power by being able to “impound” spending he didn’t support. Since that time, power over the budget has gradually shifted from the White House to Congress.

Given that Republicans have very little they want government to do, many are quite content with gridlock. Others have naïve expectations about retaking the White House. I have heard any number of high-ranking Republicans say that neither party can hold the presidency for more than eight years; therefore, the GOP is virtually a lock to retake the White House next year. Moreover, few Republicans respect likely Democratic nominee Hillary Clinton as a candidate, and many think she will be easy to beat on issues like Benghazi.

Republican members of Congress also know too well that any hint of cooperation with Democrats can whip the party’s conservative base into a frenzy that it can deny the party’s nomination to even its most senior members, such as Cantor. The belief that he was not strong enough in pressing the Republican agenda also led to the recent resignation of John Boehner.

But there are some things only a president can do. Only the president can nominate federal judges and members of the Supreme Court. The Senate may fail to confirm them, but in the end, senators may only select from among the president’s choices. And the president’s power in foreign affairs and national security is overwhelming.

As time goes by, the pressure to control the White House becomes critical, and parties historically have been willing to do what had to be done to achieve it, even if it meant nominating a candidate frowned on by much of the party’s base. This is true in both parties.

In 1952, Republicans supported Dwight Eisenhower in large part simply because he was known to be highly electable, even though much of the base would have preferred Ohio Senator Robert Taft. In 1968, they again held their noses and supported Richard Nixon because of his perceived electability after the base’s ideal candidate, Arizona Senator Barry Goldwater, crashed and burned in 1964. In 1992, Democrats got behind Bill Clinton for the same reason despite misgivings about his ethics and lack of commitment to traditional liberalism.

Because the president represents the entire country, whereas members of Congress represent only particular states or discrete districts, the president will necessarily have a broader perspective than those of his party in Congress. Voters tend to be hostile to do-nothing presidents and reward those who get things done. But Republican primary voters may prefer a do-nothing representative who votes no on virtually everything. Thus, there is inherent institutional conflict between Republican presidents and members of their party in Congress. This is less the case for Democrats.

As a congressional staff member during the Reagan administration, I saw on a day-to-day basis the tension between the White House and congressional Republicans, who were often frustrated by Reagan’s willingness to compromise and support measures contrary to conservative dogma, such as raising taxes or giving amnesty to illegal aliens. But White House lobbying, favors, and presidential leadership usually overcame their resistance.

Such institutional conflict between the president and Congress was baked in the cake by the Founding Fathers, who explicitly rejected a parliamentary system. But sometimes it creates perverse incentives for members of Congress when continued party control of that body conflicts with what their presidential nominee must do to get elected. I have never seen a member of Congress actively sabotage his party’s nominee, but I have seen many who avoided association with him lest they alienate their core constituency: primary voters.

For some years, various trends have diluted the ability of parties to exercise control and unify candidates from the top down. So-called super PACs, often backed by billionaires, mean that parties cannot do today what they used to do in the past and cut off money to those who refuse to be team players. Meanwhile the disintegration of the mainstream media and rise of alternative communications means that even the most extreme, unelectable candidates can remain competitive long past the point where they would have been forced out in the past.

This is a bigger problem for Republicans than Democrats, who created “superdelegates” from among their officeholders to help align their interests with the party’s presidential nominee. Such convention delegates are not bound to a particular candidate and are more likely to look out for the party’s institutional interests in choosing a nominee than primary voters are.

In the Republican Party, however, primary voters still exercise dominance, leaving party leaders with few options in the event voters insist on nominating a candidate who cannot win the general election. This appears to be the case now. Donald Trump is leading the GOP race and is unelectable in the view of most party professionals. This puts congressional Republicans in a difficult position, especially when their own primary elections coincide with presidential primaries. They may feel compelled to support a presidential candidate who cannot win in order to protect themselves. They may also prefer to be independent operators, free to oppose the president without fear of reprisal, rather than have a president of their own party who might pressure them to support policies contrary to their electoral base or personal philosophy.

Thus far, the GOP hasn’t been forced to choose between holding Congress or winning the White House. But if it loses badly in 2016, especially with demographics moving further and further in the Democrats’ favor, with the rising percentage of young and nonwhite voters, at least some Republicans will conclude that the party is in a crisis demanding fundamental reform. Should a Democratic president bring in a flock of new members of Congress, due to the propensity of Democrats to vote more heavily in presidential elections and fear of full Republican control of government, the urgency of reform will be all the more acute.

This will bring to a head the inherent conflict between Republicans in Congress, who often win by opposing all compromise, and the requirements for winning the White House, which demand compromise. In an era when party institutions have less power than they have had since the 19th century or perhaps ever, the Republican path to the White House is unclear. That is especially so as long as the party remains highly animated by the immigration issue, which practically guarantees that the fast-rising Latino vote will be lost indefinitely. Some Republicans may delude themselves that they can win as virtually a whites-only party, but the likelihood of such a scenario is dubious at best.

It took five straight presidential losses between 1932 and 1948 for Republicans to accept a moderate such as Dwight Eisenhower as their presidential nominee as the price of retaking the White House. Given the intensity of extreme conservatism among Republican primary voters and many of its big contributors, it may take another three White House losses before the need to win is sufficiently strong to overcome resistance to compromise and moderation, and elevate electability over rigid adherence to principle in choosing a presidential nominee.

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