Gen. Michael V. Hayden, who led the National Security Agency when it began a program of warrantless wiretaps, vigorously defended the program today, but acknowledged that it depends on a lower standard of evidence than required by courts.
"The trigger is quicker and a bit softer," said General Hayden, an Air Force officer who is now the principal deputy director of the new national intelligence agency.
...
The standard laid out by General Hayden - a "reasonable basis to believe" - is lower than "probably cause," [sic] the standard used by the special court created by Congress to handle surveillance involving foreign intelligence.
Actually, "probable cause" isn't just the lower standard used by the special court, it's also the standard required by the US constitution.
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.
As Holden pointed out in email, this also means they're completely changing their story. Previously they lied and said that the FISA courts just couldn't act fast enough. Now we find out that they hate the US constitution and federal laws.