A new poll shows U.S. Rep. Dusty Johnson leading the race for South Dakota’s Republican nomination for governor by a 10-point margin, but still below the level needed to avoid a runoff.

The KELOLAND-commissioned Emerson College Polling survey results, released Wednesday, found Johnson at 28%, followed by businessman Toby Doeden at 18%, Gov. Larry Rhoden at 17% and state House Speaker Jon Hansen at 14%. Another 23% were undecided.

Under state law, if no candidate wins at least 35% in the June 2 primary election, the top two advance to a runoff eight weeks later.

Emerson said it surveyed 413 Republican primary voters March 7-9, with a credibility interval — which Emerson said is similar to a margin of error — of plus or minus 4.8 percentage points.

Johnson also polled at 28% and had leads in two South Dakota News Watch-Chiesman Center for Democracy polls conducted last year.

In April results, Johnson had 28%, Rhoden 27%, Marty Jackley (who has since declared himself a candidate for U.S. House rather than governor) 18%, Doeden 4% and Hansen 2%. In October results, Johnson had 28% and Rhoden 27%, with Doeden rising to 15% and Hansen to 10%.

In a broader survey of 1,000 South Dakota voters, the Emerson poll found that 55% approve of President Donald Trump’s job performance, while approval ratings were 37% for U.S. Sen. Mike Rounds, 35% for Rhoden and Johnson, and 34% for U.S. Senate Majority Leader John Thune, who are all Republicans.