Senate Majority Leader Mitch McConnell (R-Ky.) took aim Friday at President Trump's former chief strategist, Stephen K. Bannon, as he looked ahead to some of the political and policy challenges the Republican Party will face in 2018.

At a year-end news conference in the Capitol, McConnell offered only a few concrete details on the legislative agenda for the year ahead, which will begin with difficult decisions for the majority party on immigration, health care and spending priorities. He said he would meet with Trump and House Speaker Paul D. Ryan (R-Wis.) during the first week of January to discuss their to-do list.

Party leaders will also confront a demanding midterm campaign landscape that has been complicated by Bannon's feud with McConnell and his attempt to use next year's primaries to oust many GOP senators loyal to the leader.

Looming over all of it is the rocky relationship between McConnell and Trump, who ended the year on a note of solidarity but have also clashed publicly in recent months. One major variable in that relationship is Bannon and the extent to which Trump sides with him over McConnell.

"Well, let me just say this: The political genius on display of throwing away a seat in the reddest state in America is hard to ignore," McConnell said when asked whether he blamed Bannon for Democrat Doug Jones's win in the special election for Senate in Alabama this month. Bannon had backed Roy Moore, the controversial former state chief justice who defeated McConnell's choice in the GOP primary, Sen. Luther Strange.

Before the general election, Moore was accused of making unwanted sexual advances toward girls as young as 14 when he was in his 30s. He denied the allegations and continued his campaign, even as McConnell and other Senate Republican leaders called on him to drop out. Bannon, however, stood by Moore, even campaigning with him on the eve of the Dec. 12 election. Trump, who endorsed Strange in the primary, also waged a final push on Moore's behalf.

Jones's victory marks a major blow to McConnell, Bannon and other Republicans who involved themselves in a race in a staunchly conservative state. When he is sworn in early next year, the Republican majority in the Senate will narrow to 51-49 over the Democrats.

Looking ahead to the midterm elections, McConnell said he'll continue his recent strategy of helping the most electable Republicans get nominated. He expressed confidence that "the White House will be in the same place I am."

The 2018 Senate map once looked ripe for GOP gains, with many more Democrats up for reelection than Republicans, including several in states Trump won. But retirements and the possibility of bruising primaries have dimmed the party's outlook.

McConnell addressed a range of topics in his Friday news conference, which came after Congress passed a sweeping tax bill and a stopgap spending measure to head off a government shutdown for at least a few more weeks.

When lawmakers return next year, McConnell will face a challenging slate of tasks, including coming to terms with Democrats on a long-term government funding agreement, which has proved elusive so far.

A more bipartisan legislative focus should be expected in 2018, he said, given the realities of a nearly evenly divided Senate. One item McConnell said he is "almost certain" to act on is a bipartisan bill easing regulations on small and medium-size banks that was imposed under the 2010 Dodd-Frank financial-oversight law. The bill, which passed the Senate Banking Committee this month, has 12 Democratic co-sponsors.

McConnell framed 2017 as a successful year for Republican senators, pointing out the tax bill, the judicial nominees they shepherded to confirmation, including Supreme Court Justice Neil M. Gorsuch, and the rollback of some Obama-era regulations.

[Judges, not tax reform, are GOP’s crowning achievement, McConnell says]

But McConnell struggled for much of the year to produce a major legislative accomplishment, toiling for months on a bill to repeal and replace the Affordable Care Act. His efforts fell short, leaving a core GOP campaign promise unfulfilled and frustrating Trump.

McConnell expressed little enthusiasm Friday for taking up further changes to the health-care system or an overhaul of federal entitlement programs. He encouraged Republicans who advocate repealing more ACA provisions to keep gathering support for their proposals, but he stopped short of any firm commitment to pursue legislation: "My view of that is, as soon as we have the votes to achieve it, I'd like to do that."

[McConnell: Entitlement reform is a nonstarter in the Senate in 2018]

McConnell's relationship with Trump, which has been unsteady throughout 2017, worsened in the wake of the Obamacare-repeal failure. But this week, Trump praised McConnell in a tweet for a "fantastic job" on the tax bill.

McConnell, who has said he is not a fan of Trump's tendency to pick fights on social media, quipped that he started "warming up" to Trump's Twitter habits this week. He declined to talk about the state of their private conversations.

While he tempered expectations on health-care reform, McConnell sounded more optimistic about the effort to find a compromise on a key immigration issue: delivering legal status to nearly a million immigrants brought illegally to the U.S. as children.

McConnell indicated earlier this week that if senators seeking a bipartisan deal could agree on legislation, he would put it on the floor. But he also said he did not see a need to address the issue before March, when an existing program that protects "dreamers" from deportation is set to expire. Senate Minority Leader Charles E. Schumer (D-N.Y.) and other Democrats are pushing to strike a deal in January.

Citing the story of how his wife, Transportation Secretary Elaine Chao, came to the country, McConnell said he supports maintaining legal immigration but said "there are improvements we could make."

"One thing I do think needs to be fixed is chain migration," he said, using a term favored by conservatives to describe laws allowing legal immigrants to sponsor family members who come here. That remark goes beyond the border-security provisions that Democrats have been generally willing to entertain as part of a compromise.

McConnell added another caveat: Having Trump's approval is crucial.

"We want to have a signature," he said. "We don't just want to spin our wheels here and have nothing to show for it."

Asked about the Senate probe into alleged Russian tampering with the 2016 presidential election and possible connections to Trump's campaign, McConnell expressed confidence in the Intelligence Committee leaders conducting it.

"It's not up to me to say when it's over; it's up to them to say when it's over," he said, referring to the panel's chairman and vice chairman, Sens. Richard Burr (R-N.C.) and Mark R. Warner (D-Va.). "I hope those guys can stay together and tell us what happened and what we need to do to prevent it from happening again."

McConnell was also asked for an update on Republican Sen. John McCain, who missed votes this week after he returned to Arizona to receive treatment for an aggressive brain tumor. McConnell, who has worked alongside him since McCain arrived in the Senate in 1987, called him "the finest person I have served with in my time here and a person for whom I have the greatest admiration."

"We fully expect to have him back after the first of the year," he said.