I think the convening power of Billionaires is hard to ignore to get things started. The US is a country run very much for that class, so working within and alongside that system may be wise.

So, i'd organise a group, possibly using some organised people of the disaffected Virginia federal government lay-off group. ;) But ideally people who can navigate their way to set up the PACs whoever they may be.

Set out clear and importantly actionable definitions of corruption and corrupt behaviour and steps taken for different degrees of corruption and how its determined. Don't forget its not a court, its a PAC so 'balance of probabilities' when it comes to possibility of corruption may even be too high a standard, certainly 'beyond reasonable doubt' would hurt the viability of weeding out corruption, ie set the bar of corrupt behaviour for withdrawing funding low and tested against regularly.

Work on ensuring all public faces are about the positive side, so instead of the negative proposition 'we are anti-corruption', err on the side of the positive proposition 'we support integrity and honesty'. Avoid the doom and gloom messaging, people like to have a positive vision especially if they're going to be required to pay for, and/or sacrifice their time in doing.

Once the PACs, at least two separate structures, are set up, ready to launch reach out to the billionaire class. Three that come to mind would be Nick Hanauer (along with Civic Ventures), Mark Cuban (Dallas Mavericks), and Anthony Scarramucci (TRIPUS, Skybridge capital), these three have all demonstrated, publicly at least, the ability to understand what corrupt behaviour looks like and crucially its ethical implications, not saying any are perfect ethical creatures themselves, they don't have to be to understand and respect the concept of the PACs.

Bring that class in, use their 'star power', but don't allow them to invest in both PACs, one needs to be kept separate from oligarchs, maybe spokespeople for the other PAC can be well known and known to be honest figures in sport, or entertainment, and well known people in local areas.

Crucially it cant matter what side of politics the participants hail from, when PAC business is being discussed or acted on the only principles are honesty and integrity and the charter which sets those out, donors and volunteers pursuing other agendas are asked to continue that in other parts of their life.

It also needn't take a representative, senator, judge, sheriff etc to call the PAC, the assessment criteria can be run and then offered to elected representatives, with an explanation of why.

When it comes to candidates, thats when it can get harder, because donors will naturally try to stack in their own political appointees. I don't have an answer for that yet, because new candidates will need some sorting mechanism.