Law enforcement wants a process useful for mass invocation (via warrant or even on bulk communication).
The "via warrant" option doesn't apply as a rationale for a backdoor. If law enforcement wants a process useful for a limtied number of specific cases, they already have it (judicially authorized planting of hardware or software bugs). The only reason to want a backdoor is to routinely snoop on bulk communication.
I hear that James Comey was once in the same position, and kept banging his head against the tree and screaming for somebody to repeal the law of gravity until the men in white coats showed up to rescue him.
Actually, he *is* a bit stupid if he's unaware of the fact that in addition to losing all credibility with sensible people, he's lost all credibility with the politicians he needs to convince. So, Jimmy, who do you want to lobby first: the ones who hate your guts for screaming "E-Mail-Ghazi!" on the eve of the election, or the ones who hate your guts for telling everybody "The Trump Kremlin Connection is real and the Trump Tower Wiretap isn't"?
I am cynical enough to suggest that if rational arguments don't work, somebody ought to try convincing the Cheeto in Chief that the DMCA is a Clinton payoff to those sad fake professional protester Hollywood people who keep mocking him because they don't want to Make America Great Again.
Nunes is so utterly lacking in self-awareness that he's actually trying to deflect attention from his hypocrisy with a childish "I'm rubber, you're glue" ploy (https://www.washingtonpost.com/news/powerpost/wp/2017/02/14/fbi-needs-to-explain-why-michael-flynn- was-recorded-gop-intelligence-chairman-says):
> "Where are all the privacy groups screaming now?" [Nunes] asked.
Well, Devin, when you find "privacy groups" that actually said that American intel agencies shouldn't be trying to listen in on *the freaking Russian Ambassador*, let us know whether there's any "screaming" echoing through the phone booth where this group holds its meetings.
Donald ought to try a "physician, heal thyself" approach, starting by throwing away his obsolete insecure phone (https://www.wired.com/2017/01/trump-android-phone-security-threat/), which could be (and probably already has been) turned into a remote-controlled bug just by tweeting him a malware link designed to catch his attention (e.g. "Miracle Lotion Can Make Your Hands Grow To Normal Size!").
Alternative Fact: "Obama was doing the exact same thing"
Real Fact: "In light of the response from Obama administration officials that there never was a point when Iraqi resettlement was stopped or banned, we are updating this ruling to Three Pinocchios." (https://www.washingtonpost.com/news/fact-checker/wp/2017/01/29/trumps-facile-claim-that-his-refugee -policy-is-similar-to-obama-in-2011/)
"As many have noted, not a single terrorist attack has come from people from those countries."
No doubt the memos have already gone out to ISIS and al-Qaeda cells to select operatives from countries where Trump owns hotels, secure in the knowledge that no security measures which threaten to inconvenience his customers will be entertained.