bzzt!, oh, sorry, that's not the correct answer. The correct answer is set out in the oath that all US Senators take upon being sworn into office[1] which reads:
>"I do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter: So help me God."
So no, sorry, the first priority is to support and defend the Constitution against all enemies, foreign and domestic, which includes the NSA. Their oath says nothing about terrorism.
>"If government agencies identify a suspected terrorist, they should absolutely go to the relevant phone companies to get that person’s phone records."
Are you done supplicating yourself fully before the police state? My copy of the Constitution (which does not contain the root password "thinkofthekids" or "terrorism") says you need not just suspicion, but probable cause for a warrant.
>"When the Bill of Rights was adopted, it established that Americans’ papers and effects should be seized only when there was specific evidence of suspicious activity."
bzzt!, again, so close! Let's look at what it really says[2], shall we (emphasis mine):
>The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
Not only do you need suspicion, but you need probable cause for a warrant or the search needs to be reasonable some other way (border crossing, subject gave consent, search subject to arrest, etc).
>Our bill would prohibit the government from conducting warrantless “backdoor searches” of Americans’ communications — including emails, text messages and Internet use — under Section 702 of the Foreign Intelligence Surveillance Act.
Again, so close! Read the fourth amendment again. Nowhere does it say "The right of US Citizens". It says "The right of the people". That means all people - citizens and non-citizens, and that distinction is important. The protections afforded under this amendment apply to everyone in the country and extend to those parties being contacted by someone from this country, otherwise the wording would be different.
[1] http://www.senate.gov/artandhistory/history/common/briefing/...
[2] http://www.archives.gov/exhibits/charters/bill_of_rights_tra...