Five months to the day after the Republican majority in the Wisconsin State Senate voted to approve Governor Scott Walker’s plan to strip most collective bargaining rights from public employees, two of the governor’s most prominent allies in the chamber have been removed from office.

Western Wisconsin State Senator Dan Kapanke and eastern Wisconsin Senator Randy Hopper were both defeated in recall elections that provided a powerful indication of the state’s anger with Governor Walker’s assault on worker rights.

Running in districts that were drawn to elect Republicans, that have consistently elected Republicans for generations, and that all backed Walker last November, the Democrats scored a pair of historic victories. “Six months ago no one would have ever expected we would be where we are tonight. The people of Wisconsin have made history,” said Senate Democratic leader Mark Miller. “Democrats, moderates, independents and even Republicans fought back against the radical Walker overreach that attacked core Wisconsin values. We fought on Republican turf and added two Democrats to the State Senate.

The Democrats did not take control of the Senate from the Republicans Tuesday, as labor, farm and community activists—who filled the streets of the state’s capitol, city, Madison, and other communities with mass protests in February and March—had hoped would be the case. While Kapanke was defeated by Democratic challenger Jennifer Shilling and Hopper was defeated by Democrat Jess King, three other Republican incumbents who were forced into recall races—Rob Cowles in the Green Bay area, Luther Olsen in the center of the state and Sheila Harsdorf in the northwest—prevailed against their Democratic challengers.

A fourth Republican incumbent, Alberta Darling, who has for many years represented a suburban Milwaukee district, was declared the victor over Democrat Sandy Pasch early Wednesday morning after a messy count that saw controversial Waukesha County Clerk Kathy Nickolaus, a Republican stalwart, fail to report the results until late in the evening. Nickolaus stirred a national outcry in April, when she reported two days after a hotly contested state Supreme Court election that she had discovered more than 7,000 additional votes for the candidate favored by the GOP and Governor Walker. And her delays Tuesday night led Democratic Party of Wisconsin Chair Mike Tate to complain at one point in the evening that “the race to determine control of the Wisconsin Senate has fallen in the hands of the Waukesha County clerk, who has already distinguished herself as incompetent, if not worse.“

The recalls of the six Republican senators all played out on conservative turf, in historically Republican districts. The uphill runs were made more difficult by the fact that national groups funded by conservative billionaires such as Charles and David Koch poured money into television advertising on behalf of the incumbents as part of what has been called “the first Citizen’s United campaign.” (That’s a reference to the US Supreme Court decision that removed traditional limits on campaigning by corporations and wealthy individuals.) Watchdog groups predicted that spending in the Wisconsin contests could exceed $40 million.

Against those odds, it is more than merely notable that Democrats were able to dramatically narrow the Republican majority in the Senate, from a comfortable 19-14 margin to a razor-thin 17-16 difference.

That one-vote GOP majority becomes significant from an organizational and policy standpoint. That’s because one Republican senator, Dale Schultz, voted against the governor’s assault on collective bargaining—which he referred to as “colossal overreach.” Schultz has been highly critical of the governor in recent weeks, and the extent to which he decided to work with the Democrats could tip the balance on labor, education and public services issues where the moderate Schultz has differed with his fellow Republicans.

That prospect unsettles Republicans and their special-interest allies, who poured tens of millions of dollars into an effort to defend the incumbents who sided with Walker. Next Tuesday, Republicans will mount challenges to a pair of Democratic senators, Jim Holperin in the northern part of the state and Bob Wirch in the southern part. Because of the uncertainty about the role Schultz will play, Republicans will work hard to displace at least one of the two Democrats—with Holperin being aggressively targeted by a Tea Party candidate, Kim Simac, who has drawn raves from Glenn Beck.

Next week’s recall voting will continue the rolling referendum of Governor Walker’s agenda that began in July, when state Senator Dave Hansen, D–Green Bay, defeated a Republican recall challenge by a 67-33 margin—the biggest victory so far in a struggle that could yet see a recall of Walker himself.

“A grassroots coalition sparked by hundreds of impassioned community members worked countless hours on behalf of a belief in Wisconsin as not just a place but as an idea worthy of preserving,” said Sandy Pasch, one of the Democratic recall candidates.

“On Tuesday night, Wisconsin spoke loud and clear with the recall of two entrenched Republicans. This is an accomplishment of historic proportions…,” said Democratic Party of Wisconsin chair Tate. “The fact of the matter remains, that, fighting on Republican turf, we have begun the work of stopping the Scott Walker agenda.”