Republican US Senators Richard Burr of North Carolina and Kelly Loeffler of Georgia are under investigation for felony insider trading crimes, including the STOCK Act.
The FBI seized their iPhones and served Apple with warrants under FISA to get their phone backups out of iCloud.
If they refused to use these malicious spying devices and did their computing locally then there wouldn't be anything useful in the remote backdoor, iCloud, for the government to take. 
People in Congress passed sweeping laws for the government to spy on Americans, and now there's a possibility that two Republican senators will be yanked out of office in handcuffs because the government used those programs against them.