ST. PAUL — For Minnesota Republicans, this weekend’s convention in Rochester won’t deliver a typical knockout punch to all of the candidates who fail to get the endorsement of the party faithful.

The 2,200 GOP delegates have a bounty of options for governor and U.S. Senate but little expectation of having the final word in selecting the nominees. The break with tradition has caused some worry that the intramural contests will drain resources and cause wounds that make it tougher to defeat a pair of Democratic incumbents who barely won their first races.

Democrats hold their own convention this weekend in Duluth, but with less drama as Gov. Mark Dayton and Sen. Al Franken are virtually assured backing. The party has ample turf to defend: It holds every statewide office and controls both chambers of the Legislature.

Republicans sense opportunity to make inroads. But some activists are riled up because GOP chairman Keith Downey advised local party leaders Wednesday of an obligation to support the candidates endorsed this weekend — a tradition some do not plan to follow.

“As a matter of mutual respect and for the integrity of the party and all involved, if party leader chooses to support a candidate running against the endorsed candidate in any primary, they should first resign their party position unless that party unit’s constitution or bylaws provide otherwise,” Downey wrote in the email, first published by the Politics.MN site run by a former party operative.

Only two Republican gubernatorial contenders have promised to abide by tradition. Hennepin County Commissioner Jeff Johnson and state Sen. Dave Thompson said they’ll drop out if someone else is endorsed. Former state Rep. Marty Seifert is leaving his options open after watching his first attempt at the office end at the 2010 convention. Former House Speaker Kurt Zellers and businessman Scott Honour say they’ll advance to an Aug. 12 primary no matter what and won’t have a large convention presence.

In the Senate race, St. Louis County Commissioner Chris Dahlberg, investment banker Mike McFadden and state Sen. Julianne Ortman have the best shot at the endorsement of delegates, who tend to hold more conservative views than Republicans who don’t attend conventions. McFadden is the only one planning a primary run whatever the convention result. Aside from a possible endorsed rival, he would likely face state Rep. Jim Abeler and other lesser-known candidates.

The endorsement brings access to vast party voter lists, mentions in party mailings and county fair-booth literature and, in some years, broadcast ads by the party. But Minnesota Republicans have struggled with debt and lean budgets in recent years, leading some candidates to question the endorsement’s value.

Zellers said he decided spending money to secure the endorsement didn’t seem prudent.

“We want to spend it on target — getting independents, getting leaning Republicans and some conservative Democrats who want jobs brought back to the state. That’s who we’re going after,” he said. “It’s not a disrespectful thing. But if you’re a Republican delegate, we’re pretty sure you’re going to vote Republican.”

On the flip side, Johnson and Thompson have flooded delegates with phone calls and targeted mailings, stressing decisions to follow their will.

“Unlike most candidates in this race, Dave has pledged to abide by your endorsement, even if it costs him his chance to be governor,” one recent Thompson mailing said.

The Republican hopefuls are harmonious in their piercing criticism of Dayton. They say voters should punish him for a health insurance marketplace plagued with early problems, for steep increases in state spending and for allowing construction of a $90 million office building for legislators.

Dayton heads to Duluth in a far different position than four years ago, when the party didn’t even let the former U.S. senator and longtime benefactor onto the convention floor. That year, he made no effort to snag the endorsement and focused on winning the Democratic nomination in a summer primary.

The state’s first Democratic governor in 20 years, he’ll use this convention to frame himself as a champion for the middle-class who followed through on a promise to raise taxes on the rich to bolster spending for schools, freeze college tuition and plug persistent budget gaps.

“None of which would have happened if we had followed the old Republican path of no tax increases and dumping the problems down the road,” Dayton said this week.

Franken also has a clear path to the fall ballot and millions of dollars at the ready.

The biggest decision before Democrats is who to endorse for secretary of state, with state Reps. Debra Hilstrom and Steve Simon vying for the open office.