President Trump announced late Monday that he would head to West Virginia to campaign on behalf of the “hardworking and spectacular” Attorney General Patrick Morrisey, who is hoping to flip the seat from Democratic challenger and incumbent Sen. Joe Manchin in the upcoming midterm elections.

Morrisey, who won the Republican primary, hopes to give the GOP a much-needed win in one of the top Senate battlegrounds as Democrats set the stage for a tough battle in November to regain control of the House.

“Will be going to the Great State of West Virginia on Tuesday Night to campaign & do a Rally Speech for a hard working and spectacular person, A.G. Patrick Morrisey, who is running for the U.S. Senate,” Trump tweeted. “Patrick has great Energy & Stamina-I need his VOTE to MAGA. Total Endorsement!"

Trump also reaffirmed his support of California’s GOP candidate for governor John Cox late Monday evening, who he says “will Make California Great Again.”

“I am hearing so many great things about the Republican Party’s California Gubernatorial Candidate, John Cox. He is a very successful businessman who is tired of high Taxes & Crime,” Trump tweeted.

Cox, who vowed to make the Golden State “livable and affordable” during an interview with Fox Business in June, will face Democratic Lt. Gov. Gavin Newsom, the former San Francisco mayor, in the November general election.

Trump predicted earlier this month that Republicans could ride a “giant Red Wave” into the November midterm elections spurred on by none other than the president himself.

“As long as I campaign and/or support Senate and House candidates (within reason), they will win! I LOVE the people, & they certainly seem to like the job I’m doing,” Trump tweeted. “If I find the time, in between China, Iran, the Economy and much more, which I must, we will have a giant Red Wave!”

Trump-backed Kansas Secretary of State Kris Kobach won the Republican primary for the state’s gubernatorial race, and candidates in three Missouri and Michigan races also won.

Republican state Sen. Troy Balderson, who also had the endorsement of the president, declared victory in Ohio's special election for a vacant House seat despite the race still being too close to call.

Democrats are widely seen as the favorites to reclaim control of the House, and are consistently leading in so-called “generic” congressional ballot polls – including districts that were once seen as solid red.

Despite coming up short in most of those races, Democratic leaders point out that the fact the races are competitive is a sign of Republican vulnerability in the fall.

Fox News’ Judson Berger and The Associated Press contributed to this report.