Pacing slowly in a dingy kitchen hallway, Republican Jeff Johnson was trying to convince the radio host on the other end of the phone that he is the one to watch in the Aug. 12 primary.

As the sounds of a Hmong banquet leaked into the echo-filled corridor in Oakdale, Johnson pledged that as the endorsed candidate he alone was capable of uniting the party and persuading swing voters to go Republican this time around.

For Johnson, the stakes are extraordinarily high. A loss in the August primary could severely diminish the power of the party endorsement. If he wins the primary but fails to woo moderate voters from supporting DFL Gov. Mark Dayton in November, Republicans will be shut out of the top office for years to come. Johnson, who has been intimately involved in the party's recent struggles and recovery, knows the weight.

"If I blow this? If I screw this up? Yeah, that will be on my shoulders," said Johnson, a former state legislator and former national committeeman for the party who is a Hennepin County commissioner.

A slim 5-foot-9 with closely cropped hair that he often rakes to the side with his hand, Johnson looks like he could be anyone's Minnesota neighbor. And he could be. Johnson is one of the most common last names in Minnesota. There are more than 400 Jeff or Jeffrey Johnsons registered to vote in the state and 10 in his hometown of Plymouth alone.

"Great name," said former Minnesota House Speaker Steve Sviggum, a Johnson campaign co-chair. "Jeff Johnson is Minnesota nice."

Johnson hopes his nice-guy appeal will help him best his rivals in this summer's rare competitive Republican primary. He faces former House Minority Leader Marty Seifert, who has pitched his campaign from a rural Marshall base; former House Speaker and Maple Grove Rep. Kurt Zellers, whose support weaves through the establishment metro, and Wayzata businessman Scott Honour, who could pour significant cash into his campaign. But Johnson has the party endorsement.

At the Oakdale event, Johnson slips in affably among crowds. From his Democratic colleagues to his former high school teacher and neighbors, the 47-year-old father of two is described as genial and well-liked. But unlike some politicians, Johnson is not a charismatic, life-of-the-party type. Whether he's at a parade, the Hmong banquet or even a fundraiser in his own home, his style leans toward mingling, good-natured jokes and a willingness to take questions from all comers.

When Johnson needed emergency surgery for a perforated stomach recently, he was promptly flooded with bipartisan well wishes — including from all his rivals. "That is as much about demeanor or personality as it is about anything," said Johnson of his cross-partisan appeal.

The quest for crossovers

Johnson has yet to prove he can win conservative Democratic or independent votes in a close contest.

When he served in the House, he won every two years from 2000 to 2006 in a heavily GOP district. He ran unopposed for re-election to the Hennepin County Board's District Seven and won easily in the GOP stronghold. He ran one statewide campaign for attorney general in 2006 and lost to DFLer Lori Swanson by more than a dozen percentage points.

Johnson hails from the party's conservative wing. He was president of the 5,500-member Calvary Lutheran Church of Golden Valley four years ago, when it broke with the Evangelical Lutheran Church in America over the ELCA's decision to allow gay pastors. As commissioner, Johnson created a Golden Fire Hydrant award on his blog — to the dismay of some colleagues — as a way to highlight examples of government waste in the county.

On the Hennepin Board, Johnson often is on the losing end of lopsided votes. He was the lone "no" vote against approval of a light-rail plan in July. He was the only commissioner to oppose a compromise with Minneapolis over garbage disposal. He was the only one to vote against the county's 2013 budget and the county's decision to contribute to a bike-sharing program.

"He is the one on most of our 6-1 votes, but he almost always tells us and the listening public why," said Hennepin County Commissioner Linda Higgins, a former DFL state senator who won her board seat in 2012.

In May, while striving to secure party endorsement, Johnson told a Tea Party group that if elected, he would "go all Scott Walker on Minnesota," a reference to the Wisconsin governor who has become a darling of the far right for his unyielding stance on unions, taxes and other issues. The statement got a roar from the crowd — and delighted Democrats. In fundraising appeals, Dayton and his allies regularly remind voters of Johnson's voluntary alignment with Walker.

Johnson has not backed away from his statement. He says he agrees with much of what Walker did. Johnson said that as governor, he would work to cut not just the rate of growth in state spending, but actual year-to-year reductions overall. Unbidden, he says on the stump that he supports making Minnesota a "right to work" state as a means of breaking union power. In such states, unions are barred from requiring workers to join or pay dues as a condition of employment.

To winnow spending, Johnson says he would audit state programs, starting with human services, and defund those that fall short of expectations. He acknowledged that such a process could take years.

Johnson says he would differ from Walker stylistically. Walker's confrontational manner earned him plaudits from Republicans, but drove throngs of union members and others to the Wisconsin Capitol in raucous protests that made national headlines for weeks and drove a recall attempt that proved unsuccessful. "I'm more low-key. I'm not a real big bomb thrower," Johnson told a supporter at a recent Beer and Bacon fundraiser in Minneapolis.

Digging in

In recent years, however, he has been part of blowing up and stitching together the same party he now hopes will bring him victory. As a national committeeman, Johnson, together with former state Auditor Pat Anderson, pushed the party in 2011 to face the mounting debt and messy bookkeeping that brought it to the brink of bankruptcy.

"People trusted him and he absolutely did the right thing, but he did it in a measured way," Anderson said.

The party underwent a painful transition that year, owning up to $2 million in unpaid bills. It's on its third chairman in as many years.

In 2012, Johnson came to the fore again, when divisions between libertarian and establishment Republicans threatened to crack the party wide open. At the state convention that year, when U.S. Rep. Michele Bachmann was nearly denied a chance to go to the national convention in favor of a Ron Paul supporter, Johnson took to the stage to demand activists "get over" their ill feelings and get along.

"Every faction in the party — and we have real factions in the party — feels like I want them in the party," Johnson said in July, sitting in his Golden Valley campaign office. "And I do."

In return, the party is going all out to prove it can defend Johnson and its other endorsed candidates.

Volunteers down to state Republican Party Chairman Keith Downey have worked the phones on Johnson's behalf, even though it means going against two former legislators and a moneyed businessman.

With a dozen offices across the state and 19 field staffers, the party has made more than 150,000 calls and knocked on at least 8,000 doors by midsummer on behalf of its endorsed slate.

House Minority Leader Kurt Daudt, R-Crown, hopes the effort will set Johnson apart in the crowded primary field.

"I think he's got the advantage, given the endorsement," said Daudt, who managed Seifert's 2010 campaign for governor. This year, Daudt said, he's supporting Johnson.

Rachel E. Stassen-Berger • Twitter:

@RachelSB

Data editor Glenn Howatt contributed to this report