RUTHFULLY YOURS

Mr. McCarthy’s victory ended the uncertainty that House Republicans had faced since House Speaker Paul Ryan (R., Wis.) announced in April he would retire at year’s end.

Three years after he unexpectedly withdrew a bid to become House speaker, Mr. McCarthy completed his rebound at a low point for House Republicans. After last week’s midterm elections, Democrats have so far won a net of 34 House seats and have a chance at picking up as many as 38.

“We took a beating in the suburban areas,” Mr. McCarthy said after the leadership elections. He said Republicans were willing to work with House Democrats, but that the GOP would block moves from Democrats who exceed their oversight authority regarding the Trump administration. “If their agenda is simply investigations and impeachment, and not focusing on the hardworking American public, we’ll be there to defend the American public,” he said.

Democratic leaders have said they plan to focus on transparency in politics and oversight of the Trump administration next year. They have cautioned Democratic lawmakers to tread carefully around impeachment, which could spark political backlash.

Mr. McCarthy’s defeat of Mr. Jordan isn’t likely to end the power struggle between House GOP leadership and its more conservative wing, particularly the House Freedom Caucus, a group of roughly three dozen of the House’s most conservative Republicans. Mr. Jordan helped found the group in January 2015.

“We speak for millions of Americans that feel like this place has forgotten them—that hasn’t changed,” said Rep. Mark Meadows (R., N.C.), chairman of the Freedom Caucus and a close ally of Mr. Jordan.

Mr. Meadows said it was important that Mr. McCarthy’s election hadn’t gone unchallenged. “To have any dissenting votes is certainly saying that at least we didn’t just automatically go out and crown somebody as the new leader,” he said.

It isn’t yet clear whom Mr. McCarthy will be squaring off against next year in the House.

House Democrats will hold their leadership elections in two weeks. On Wednesday, new members met for the first time with incumbents. The caucus appeared on track to promote the top three leadership positions to the majority, but a small group opposing Minority Leader Nancy Pelosi (D., Calif.) grew louder on Wednesday, with its members saying they had plans to oppose her.

Minority Whip Steny Hoyer (D., Md.) is pushing to become majority leader and Assistant Leader James Clyburn (D., S.C.) is running for the whip spot. The races for lower-level leadership spots are crowded with young members trying to ascend in a caucus that has had the same leader for nearly 16 years.

Earlier Wednesday, Senate Majority Leader Mitch McConnell (R., Ky.) and Minority Leader Chuck Schumer (D., N.Y.) were re-elected to their posts in party elections for the next session of Congress.

Messrs. McConnell and Schumer were each re-elected by acclamation in separate, closed-door meetings of Senate Republicans and Democrats Wednesday morning. On the GOP side, Sen. John Thune (R., S.D.) was elected to the No. 2 job of whip, succeeding current Majority Whip John Cornyn (R., Texas), who is facing term limits in the post. Mr. Cornyn is expected to remain in GOP leadership as a counselor to Mr. McConnell.

Mr. McConnell said he looked forward to continuing to make progress in his priority, “the confirmation of lifetime appointments to the judiciary.”

In the most competitive Senate GOP race, Sen. Joni Ernst of Iowa beat Sen. Deb Fischer of Nebraska for the position of Senate GOP conference vice chairman, a steppingstone into the elected leadership ranks. Mrs. Ernst’s election adds a woman to the top ranks of the Senate GOP, which has come under criticism for the all-male team that has assembled for weekly news conferences, particularly during the GOP effort to repeal and replace the 2010 health-care law and other contentious legislative debates.

“I’m looking forward to the opportunity to share our wonderful, overwhelming message of prosperity,” Mrs. Ernst said after the election. Mrs. Ernst is up for re-election in 2020 and could face a tight race in Iowa, traditionally a swing state.

House Republicans also added a new woman to their leadership: Rep. Liz Cheney (R., Wyo.) will replace Rep. Cathy McMorris Rodgers (R., Wash.) as chairwoman of the House GOP conference. Ms. Cheney, the elder daughter of former Vice President Dick Cheney, said her father had given her some advice. “He told me not to screw it up,” she said.

Mr. Schumer on Wednesday said Senate Democrats had fared better than many had expected in last week’s midterm elections, even though Republicans are expected to expand their current 51-49 majority next year.

“When we stood here two years ago, we faced a daunting electoral map, the worst in decades,” Mr. Schumer said. “Much to the surprise of the prognosticators who thought we’d lose a whole bunch of seats, we didn’t.”

With Democratic Rep. Kyrsten Sinema’s victory in Arizona this week, the Democrats have now flipped two Senate seats and the Republicans three, with the Florida Senate race still outstanding and a Nov. 27 runoff election still to come in Mississippi.