On Wednesday morning, 14 September, FBI agents descended on the Madison home of one of Wisconsin Republican Governor Scott Walker's closest aides, Cynthia Archer. The federal agents seized Archer's computer files and other documents. A wider investigation involving another Walker aide may be in the works. The FBI raid has breathed new life into the hopes of Democratic organisers in Wisconsin as they decide whether to launch a recall campaign against Walker himself.

This spring Walker and a Republican-controlled Legislature passed a law curbing the power of public employee unions. That law prompted recall elections this summer of six Republican senators, two of whom were replaced by Democrats. Walker was the obvious next target, but Democrats have been wavering. The recent investigation may increase their resolve to proceed with a gubernatorial recall.

Archer, a long-time Walker loyalist and staffer, served for three years as director of administrative services for Walker while he was Milwaukee County executive, including during his campaign for governor. She helped craft the county budgets that defined Walker as an anti-union, anti-tax conservative. Archer then took a high-paying position in Walker's administration when he became governor in January 2011. Last week's FBI raid appears focused on whether she and another top Walker aide used public time for political purposes. If Walker is significantly connected to any such transgressions, it will add impetus to a possible recall election next year.

Presently, a recall of the governor looks improbable. To force an election, volunteers would need to collect over 250,000 signatures. That this summer's recalls failed to change the balance of the Wisconsin state senate will, however, discourage many Democratic volunteers. Even if they get Walker's name on the ballot, the Democrats do not have an obvious challenger. A recent poll showed (pdf) that former US Senator Russ Feingold would beat Walker in a recall election, but the popular Democrat says he won't run for office in 2012.

Yet Walker's political infallibility may be diminishing. Last May, the Milwaukee Journal Sentinel reported that Darlene Wink, a Walker staffer, had used public time to post partisan opinions on the paper's online comment walls. Walker had been Milwaukee's County executive at the time and was then running for governor. Wink resigned when confronted with the charges. This incident did not affect the outcome of the governor's race; it did prompt a local investigation, which is now apparently also a federal investigation, into misuse of public time for political purposes.

The current investigation so far seems to be focusing on two high-level figures very close to the governor. Investigators are using "John Doe" proceedings to compel testimony from witnesses and keep them from discussing the case in public. So we know very little. What we do know is that in addition to Archer, the second high-level Walker loyalist in the spotlight is Tom Nardelli, Walker's former chief of staff at Milwaukee County. Like Archer, Nardelli got a plum position in state government when Walker became governor. And like Archer, Nardelli abruptly quit his job at the state this summer as the investigation heated up.

Walker has successfully advanced his own political career by presenting himself – a self-proclaimed "preacher's kid" – as an ethical and honest politician. He rose to power in 2002 in a Milwaukee County special election to fill the seat of an incompetent Milwaukee County executive whose corrupt aides triggered a pension scandal that taxpayers are still paying for. A Republican in Wisconsin's most populous and Democratic county, Walker used this office to position himself to run for governor. If Walker's image as a straight arrow is tarnished, he will be much more vulnerable to a recall.

Due to the secret nature of the current Wisconsin investigation, we may not know for weeks whether prosecutors will bring charges, precisely what violations of the law are being investigated, and who will be in the frame. And even well-documented charges of political misconduct do not always yield convictions. So, opponents of Walker should be careful not to accuse his aides – much less Walker – of wrongdoing until all the evidence is made public.

But if Walker is tainted by this investigation in any significant way, then re-energised Democrats will almost certainly organise a recall. And that would have a fighting chance of success.