After the assassinations of 1968, the US government routinely protects candidates, even before they have the nomination.
Given the threat to democracy and the nation as a whole, from the hacking of party and campaign data operations, including e-mails, I do not think there is any alternative to NSA, or maybe another agency, providing similar routine protections.
As with Secret Service protection of candidates, office holders, and families of office holders, this will raise complex questions about privacy, trust and responsibility. A compromise, I suppose, would be to rely on the private sector, with appropriate and individualized government agency supervision. But, with the stakes so high, that’s a big risk. Would you hire Blackwater to provide candidate protection?
I wonder when this will be proposed, and when it will happen. Maybe not till after this election cycle, given the political vulnerabilities on both sides.