A leading Republican super PAC has retreated from the airwaves in West Virginia, as GOP hopes of ousting a Democratic senator in the most pro-Trump state of the 2016 election have faded in the final days of the midterm campaign.

After spending millions on the air in recent months, the Senate Leadership Fund is no longer airing television advertisements in the race, spokesman Chris Pack confirmed to The Washington Post. The organization, which had invested $7 million since Labor Day, concluded its commercials this week.

The super PAC, which is aligned with Senate Majority Leader Mitch McConnell (R-Ky.), is making a more modest $150,000 investment in get-out-the-vote efforts and digital advertising this week, Pack said. The group has also been adding money to other, more pressing contests.

While the group did not place any reservations for airtime, the choice not to invest in more television ads at the end of the race highlights the GOP’s dwindling confidence in its ability to defeat Sen. Joe Manchin III, a centrist Democrat who has frequently sided with President Trump. Manchin is facing state Attorney General Patrick Morrisey (R).

The ad decision comes as both parties make last-minute money moves reflecting their biggest priorities and vulnerabilities in the fight for control of the Senate. Democratic groups are sending reinforcements this week to Minnesota to help Sen. Tina Smith, signaling potential concern in a race that has been under the national radar.

Republicans are trying to keep and possibly add to their 51-to-49 Senate majority, hoping to capitalize on a favorable map that includes plenty of races in states that Trump won. Polls show tight contests in several battlegrounds that stand to decide which party will control the chamber.

In addition to West Virginia and Minnesota, strategists in both parties are watching Florida, Indiana, Missouri, Montana, New Jersey, North Dakota, Arizona, Nevada, Tennessee and Texas.

Nonpartisan analysts regard Republicans as the favorites to keep control of the Senate. But Republicans are not favored to keep the House, given the many suburban swing districts in play where Trump is unpopular.

Trump won more than 68 percent of the vote in West Virginia — his largest share in any state — and he plans to campaign there Friday. Recent public polls show Manchin leading Morrisey by single digits. Republicans have privately voiced some pessimism about the race during the past several weeks, although the ­Democratic-led Senate Majority PAC remains on the air.

Manchin was the only Democrat who voted for Supreme Court Justice Brett M. Kavanaugh’s confirmation. Republicans have aggressively pointed to Kava­naugh’s contentious confirmation fight in an effort to motivate people to vote Republican in the more conservative states.

The Democratic Senatorial Campaign Committee, meanwhile, started its first ad campaign in the Minnesota race Thursday. Smith is facing state Sen. Karin Housley (R). The DSCC is spending about $700,000 in the effort.

The Senate Majority PAC and Emily’s List, two other Democratic groups, are combining forces for a six-digit investment in digital and mail advertisements in the contest, according to strategists at the organizations.

Smith was appointed to replace Democrat Al Franken, who resigned in January following allegations that he touched women inappropriately. Smith had been lieutenant governor of Minnesota.

The GOP-led Senate Leadership Fund added about $5 million to its existing ad buys in Indiana, Montana, Missouri and Tennessee, according to a strategist familiar with the group’s spending. The strategist spoke on the condition of anonymity to be candid about the allocations.

Democratic incumbents are fighting for their political survival in the first three states, all of which went to Trump in 2016. In Tennessee, another Trump state, both parties are battling for an open seat created when Republican Bob Corker decided not to seek reelection.

The Senate Leadership Fund also is sending more than $2 million to a super PAC supporting Florida Gov. Rick Scott (R), the strategist said. Scott is trying to unseat Democratic Sen. Bill Nelson in an expensive contest where Republican optimism has faded in the past few weeks.

Super PACs such as the Senate Leadership Fund and the Senate Majority PAC can raise unlimited sums of money from donors. But they cannot coordinate strategy with candidates.

The Republican leanings of West Virginia in federal elections initially fueled GOP hopes of picking up the Senate seat there. But a divisive and bruising Republican primary and Manchin’s record — a former governor, supporter of Trump on the environment and backer of Trump’s two Supreme Court nominees — have complicated their task.