U.S. Senate Majority Leader John Thune plans to visit several states with competitive Senate races in the coming weeks as Republicans try to retain their majority. He told CBS News he would go to North Carolina on Thursday, followed by Nebraska, Kansas, Minnesota, Florida, South Carolina and Ohio, as well as two stops in Iowa. Some appearances will be fundraisers.

Thune campaigned in Georgia last week with Representative Mike Collins, who is seeking to unseat Democratic Senator Jon Ossoff. Thune also attended fundraising events in New York earlier this week. He said he had offered to help candidates when useful and to stay out of the way when that would better serve the campaign.

Thune has faced criticism from the Republican right and at times President Donald Trump over his assessment of the Senate’s ability to pass the SAVE America Act, an elections bill backed by Trump and allies. During the primaries, Thune said his endorsement might not help certain Republican candidates. He said the party is now in the general-election phase.

Senate Republicans are preparing to spend heavily on the midterms. The Senate Leadership Fund and affiliated groups said in August they had raised more than $500 million for candidates. Republicans are defending 53 Senate seats. Although the map initially looked favorable to the GOP, several states have become more competitive for Democrats as the unpopular war with Iran continues and voters focus on affordability.

Thune described the contest for the Senate majority as uncertain, hinging on several close races. He said Tuesday that the election was about 35 days away. Republicans believe they are well positioned and have historically outperformed polls, he said, but the result will depend on their execution in the final stretch.