Republicans will keep control of the House and Senate because voters won't want to rock the boat on the economy, according to longtime market strategist Mark Grant, who predicted a Trump victory ahead of the 2016 election.
"I've been on Wall Street 44 years. The economy continues to drive the elections, both the midterms and the presidential elections," Grant said in a "Squawk Box" interview. "I think that's going to be the defining force today."
Grant's prediction for a GOP sweep on the morning of Tuesday's midterm election runs counter to consensus expectations of the Democrats winning the House. Republicans are expected to keep their slim majority in the Senate.
"The reason is there is a tremendous amount of people that have been helped by this economy. They have jobs, their wages have gone up, they're living better, and they don't want to jeopardize it," said Grant, chief global strategist at investment bank B. Riley FBR.
The economy since Trump took office has picked up, with five of the seven quarters since January 2017 recording growth near or above 3 percent. The first estimate of third-quarter gross domestic product showed an increase of 3.5 percent after the prior quarter's 4.2 percent advance.
Trump, who wants to see sustained 3 percent growth, credits his agenda of tax cuts and business deregulation for jump-starting growth after years of struggling since the 2008 financial crisis. Critics of the president argue his predecessor, Barack Obama, teed up the economy for success.
"From a market perspective, I'm hopeful Republicans maintain control of both the House and the Senate," said Grant, who argued that Democrats winning the House, or winning the House and the Senate, would put Trump's economic agenda at risk, which could stymie the advance in stocks.
On the morning of Election Day 2016, Grant said investors would be smart to buy stocks in the event of a Trump surprise. He had been saying ahead of the voting that Trump could win. Conventional wisdom then was that Democrat Hillary Clinton would win the presidency.
Last month's horrible stock market notwithstanding, the Dow Jones Industrial Average is up nearly 39 percent since the 2016 election. Over the same period, the is up nearly 28 percent and the Nasdaq has gained 41 percent.