WASHINGTON — The Republican Party continues its disciplined march toward an impressive lineup of candidates this fall, when it hopes to wrest the Senate majority from Democrats and control both chambers of Congress during President Barack Obama’s final two years.

Tuesday’s primaries produced another batch of Senate nominees who seem about as promising as party leaders could have hoped for. There’s still plenty of time for stumbles, of course. But so far, the GOP appears to be sidestepping the type of gaffe-prone and fiercely ideological candidates who blundered into excruciating losses in 2010 and 2012.

As they did Tuesday in Iowa, Republican activists have accomplished this by blurring the differences between tea party enthusiasts and the party’s corporate and “country club” wings. Tea partyers are largely justified in saying they’re winning the larger ideological struggle by pulling the entire party rightward. But establishment Republicans are happy to be called “nominee.”

Suspenseful or not, Tuesday’s results confirmed that Republicans will have top-tier nominees in South Dakota and Montana, where long-time Democratic senators are departing or have already left.

Former Gov. Mike Rounds’ primary win in South Dakota puts him in a category with Rep. Shelley Moore Capito, who won the GOP Senate nomination last month in West Virginia. Both are well-established politicians favored to pick up Democratic-held Senate seats in states Obama lost badly. Businessman Rick Weiland was unopposed in South Dakota’s Democratic Senate primary.