Trump’s Democratic challenger Joe Biden is the projected winner in Michigan, which Trump, a Republican, carried in 2016.
Michigan Court of Claims Judge Cynthia Stephens made the ruling during a court hearing on Thursday (Nov 5).
She said she planned to issue a written ruling on Friday.
“I have no basis to find that there is a substantial likelihood of success on the merits,” Stephens said.
Campaign officials for Trump have said they filed the suit to stop the counting in Michigan and gain greater access to the tabulation process.
The lawsuit was a “messaging exercise,” said Bob Bauer, senior advisor on Biden’s campaign.
“It has no other purpose than to confuse the public about what’s taking place and to support their baseless claims of irregularity,” Bauer said in a call with reporters.
Nationally, Biden inched closer to victory on Thursday in an exceedingly close US election hinging on razor-thin margins in a handful of states.
Trump has launched a flurry of lawsuits across the country.
In another setback for Trump on Thursday, a judge in Georgia denied a request by his campaign for an order requiring Chatham County to separate and secure late-arriving ballots to ensure they are not counted.
A Trump campaign spokeswoman did not immediately respond to requests for comment on the Georgia and Michigan rulings.