Russ Feingold’s coast-to-coast profile as a progressive stalwart is paying off.

In his campaign against Republican U.S. Sen. Ron Johnson, Feingold, D-Middleton, has leveraged his national stature to become the top fundraiser among all Senate candidates challenging an incumbent.

That fundraising bounty has a flip-side, Feingold’s opponents say: the abandonment of his former pledge to collect most of his campaign money from Wisconsinites.

Feingold signaled last year that he would not renew the pledge, and as 2015 wound to a close, his share of out-of-state fundraising increased. In the fourth quarter, nearly three-fourths of the itemized individual contributions to Feingold’s campaign were from outside Wisconsin.

Feingold’s campaign counters that it has bested Johnson, R-Oshkosh, in winning support from small contributors — often people of modest means.

Johnson also is getting plenty of financial firepower from beyond the Badger State.

Two super PACs funded in part by wealthy out-of-state donors have formed to support Johnson. So far, none have surfaced to support Feingold.

For a typical candidate, the issue of in-state campaign funding might be marginal, said Mark Graul, a state Republican strategist not affiliated with the Johnson campaign.

But Graul insists that for Feingold, who cultivated an image as a straight arrow who’s unmoored to outside interests, it could be more problematic.

“It’s a double-edged sword in a way that it isn’t for most other candidates,” Graul said. “He really built his image in Wisconsin, over many years, as someone who really was different.

“What we’re seeing now, in his attempt to get his old Senate seat back, is sort of throwing the old Russ Feingold stuff out the window.”

‘A national campaign’

Jason Rae, a Democratic National Committeeman from Milwaukee, said it should be no surprise that donors across the country are supporting Feingold.

The Wisconsin seat is viewed as one of the top pickup opportunities for Democrats seeking to regain control of the Senate.

“It really is becoming a national campaign for a few Senate seats,” Rae said.

Feingold developed a reputation as one of the Senate’s leading liberals during his three terms in the chamber, from 1993 to 2011. His co-sponsorship with Republican Sen. John McCain of a sweeping campaign finance law gave him national visibility, as did his outspoken criticism of free-trade agreements, the Iraq War and increased domestic surveillance after the terror attacks of Sept. 11, 2001.

“He’s a known entity that people have experience with,” Rae said.

After Johnson ousted him in the 2010 election, Feingold used his national profile to launch a political action committee, Progressives United, that advocated for progressive causes.

Feingold launched his bid to return to the Senate last year. He raised more than $7.4 million for his campaign through Dec. 31, the most recent deadline to report those figures to the Federal Election Commission.

That places Feingold first in fundraising among all Senate candidates challenging an incumbent and second among non-incumbents, according to the Center for Responsive Politics, a nonpartisan nonprofit that tracks money in politics.

Only Kamala Harris, a Democrat running for an open seat in California, raised more.

Of the $6.9 million in individual contributions that went to Feingold in 2015, 38 percent came from in-state contributors.

Feingold campaign spokesman Michael Tyler said in a statement that his support from Wisconsinites is strong.

“While Sen. Johnson now has two super PACs backing his campaign, Russ is proud to have the support of over 27,000 Wisconsin contributors,” Tyler said.

“That difference — Russ’ broad grassroots support and enthusiasm versus Ron Johnson’s billionaire-funded operation, is what matters in this election.”

Contributions from California, New York

The Johnson campaign notes Feingold has collected nearly as much from the liberal bastions of California and New York as he has from Wisconsin. That includes itemized contributions, or those from individuals who give $200 or more to a candidate in a single cycle.

Johnson also has collected a lot of contributions from outside Wisconsin, albeit by a lesser margin.

In 2015 he collected about $5.2 million from individual contributors, according to his campaign. About $2.5 million, or 48 percent, of that came from in-state.

Among the 62 active Senate candidates this cycle who got at least $100,000 in itemized contributions, Johnson ranks 28th in the percentage of contributions he received from in-state donors. Feingold ranks 47th, according to figures provided by the Center for Responsive Politics.

Feingold first made the in-state donor pledge in his initial Senate bid in 1992 and followed in his three subsequent campaigns.

Last year, when Feingold acknowledged he would not adhere to the pledge in this campaign, he said it never was meant to be permanent. The pledge no longer makes sense, Feingold argued, after Citizens United and other court rulings unleashed an era of rampant outside spending in politics.

But Johnson spokesman Brian Reisinger said Feingold’s about-face shows he has jettisoned the principles that once guided him.

“Wisconsinites no longer recognize the man who made a promise ‘for the future’ on his garage door 25 years ago, but elite liberals in California and Massachusetts know him well,” Reisinger said.

Super PACs back Johnson

Wealthy contributors are organizing their own groups to aid Johnson.

They’re forming super PACs, or independent committees that support or oppose a candidate. Such committees may raise or spend in unlimited amounts — unlike candidates, whose campaigns face limits on how much they can collect from one individual.

A super PAC, Let America Work, formed last year to back Johnson. It had raised nearly $400,000 through Dec. 31, with the largest contributions coming from Milwaukee doctor Michael Kubly, Florida financial executive Jeffrey Diermeier, former Wisconsin GOP gubernatorial candidate and businessman Terry Kohler, and the La Crosse-based convenience store chain Kwik Trip.

Another super PAC recently surfaced to support Johnson, guided by some of Illinois’ top Republican contributors, according to a recent Politico report.

The group, Citizen PAC, is led by Ronald Gidwitz, a Chicago-area business executive, Politico reported.

One of its backers is Richard Uihlein, an Illinois resident who’s CEO of Pleasant Prairie-based Uline Corp. and a leading contributor to GOP campaigns in Wisconsin and Illinois.

Other members of its steering committee include John Rowe, former CEO of Exelon Corp., Barry MacLean, CEO and chairman of MacLean-Fogg Company, and Haley Barbour, a former Mississippi governor and former chairman of the Republican National Committee.

Outside groups supporting pro-choice causes and environmental conservation also have lined up to oppose Johnson.

The national significance of the race means Wisconsin airwaves are expected to be flooded between now and November with ads by outside groups.

Feingold urged Johnson early in the campaign to sign a pledge to discourage outside spending in the race — a move Johnson has resisted.