Vice President Mondale has taken the apparently unprecedented step of asking for a direct hand in the selection of U.S. district court judges in Minnesota via a screening commission he would dominate.

Mondale's proposal: an eight-member bipartisan selection commission to which he would name four and Minnesota's new Republican senators, Rudy Boschwitz and David Durenberger, each would name two. Boschwitz is willing. But Durenberger balked, objecting to the odds and asserting that Mondale's method violated President Carter's.

Durenberger was referring to Carter's executive order last fall which asked senators to forget partisan judicial patronage and to name screening groups to aid in the finding of candidates for the district court bench.

"The idea of the vice president's putting four people on such a commission flies in the face of the president's executive order," Durenberger said. "The executive order says the senators would have the responsibility of recommending to the president what we believe to be qualified candidates for judgeships. We would go the comission route to do that, but it's a question of how we do it."

Traditionally, although the president appoints federal district judges with the Senate's advice and consent, the president's designation is a confirmation of the choice by a state's senior senator -- thanks to "senatorial courtesy."

Mondale's bid for a piece of the action results, presumably, from the fact that both of the state's senators are now Republicans. They were elected last November in what has been called the "Minnesota Massacre" after divisive Democratic primaries in the wake of Sen. Hubert H. Humphrey's (D-Minn.) death.

Mondale is now the leader of Minnesota's Democratic Farmer-Labor Party.

Before the November election the appointment of new judges in Minnesota would have been relatively simple. But the bill creating 117 new federal district court judges, including two for Minnesota, prompted Carter's executive order setting forth guidelines to end, or at least minimize, patronage in the judiciary.

Boschwitz told reporters that he figured that in the end "they'll appoint who they want to appoint." But he added that with a screening panel, merit would be more of a factor. Durenberger said he welcomed the vice president's participation because he is form Minnesota, but said it should be limited to making recommendations for the selection commission.

In Washington, a Mondale spokesman would say only that the vice president's office was trying to work out a process for the appointment of outstanding judges with bipartisan support.

Appointment to the U.S. circuit courts of appeals are made by President Carter with the aid of the U.D. Circuit Judge Nominating Commission created by executive order soon after Carter's inauguration. During his election campaign Carter pledged he would appoint all federal judges under a merit plan.