The House may flip, and the U.S. will continue its withdrawal from global affairs.

As the vacancies in Republican districts continue to grow, the likelihood of the GOP maintaining control of Congress will continue to shrink.

Republicans’ coming difficulty in Southern California is not limited to replacing Royce and Issa: They were two of four GOP incumbents reelected in Orange County districts won by Hillary Clinton. The trend here reflects a much more widespread problem for Republican politicians in suburbs throughout the country, as many higher-income, well-educated voters who have reliably supported economically conservative candidates recoil from Trump’s combative brand of populism.

In 2016, these voters supported familiar incumbents like Royce even while turning to Clinton at the top of the ballot, but it will be much harder for a less recognizable Republican to maintain their loyalties this fall. Midterm elections are usually decided less by persuading independent voters than by inspiring committed partisans to vote.

The likely partisan changeover in Washington is of less long-term significance than the worldwide ramifications of the continued U.S. withdrawal from our global responsibilities. Since Trump’s election, competitors such as China and Russia have become increasingly assertive in their respective regions and beyond.

As a result of the president’s unpredictability and volatility, our historic allies in Europe, Asia and Latin America now look elsewhere for guidance, reassurance and support. Congressional majorities can switch back and forth every two years. But reliable long-term relationships with world leaders are cultivated and strengthened over much longer periods of time. The loss of trust that can result from a broken promise is not automatically restored after the next election.

A generation of American leaders including former Vice President Joe Biden, Arizona Sen. John McCain and Royce have devoted their careers to carefully developing, fostering and protecting our country’s international reputation. The question is not only who will emerge to repair the damage in Trump’s wake, but also how many years will be required to heal the breach. Without committed globalists like Royce, that task now becomes even more difficult.