Buck and Darlene don't have financial incentives to attack Iran. Our richest and 'wise' leaders who had the resources and time to better the world, failed to do so. The argument you present is looking pretty frail, in light of the last decade. Also, in previous centuries, it wasn't possible for direct voting to be effective in the US: The nation is huge in size. It wouldn't have been easy to collect votes quickly. With a (free) smartphone in hand, anyone can instantly check out a voting measure and cast their opinion on it.
Secondly, I mentioned that there should be laminated receipts from the voting machines. Every voter may ask for it after casting their vote. Their cellphones can also have a QR code, so they they can go into the local print shop to immediately have their voting record printed out. Plus, open-source voting. That means instead of Diebold making the software, the federal government does, which has to allow inspectors from any state to make unannounced audits of the software chain.
Thirdly, I already mentioned who the voters are: the ones who cast an vote. Requiring absolutely 51% of EVERYONE is unrealistic. Instead, the voting pool should adjust according to how many people cast a vote. So if 5,000 people cast votes, 2,501 have to say 'Nay' to prevent a pardon. We can require pardons and other voting things to have 60 day deadline. The first 30 days are an announcement and commentary period, the later 30 days are for the actual voting. This helps prevent secret 'riders' and whatnot being free of scrutiny or getting a surprise vote.