Whenever they have probable cause, or when they have definite evidence.
Obtain a warrant to search for terrorists
In the Bill of Rights the fourth amendment says the government must have a warrant and probable cause to search and/or seizure of your property.
(in the US) Only government agents properly authorized by a judicially issued warrant have the legal authortiy to search a residence. In order to obtain such a warrant they must prepare an affidavit to present to a judge, setting forth the specific probable cause supporting the request. If the judge does not find sufficient probable cause to issue the warrant the affidavit will be denied.
To obtain a warrant, law enforcement officials need to present probable cause to a judge or magistrate, who will then issue the warrant authorizing the search or arrest.
A warrant is a court order that allows police to perform an action, like search a home or obtain a person's phone records. The government should not be able to wiretap phones with a warrant to do so. Otherwise, the government is violating the privacy of innocent citizens.
The time it takes for police to obtain a search warrant can vary depending on the circumstances, but it usually takes a few hours to a few days.
probable cause
To obtain a search warrant, a law enforcement officer must present evidence to a judge or magistrate showing probable cause that a search is necessary to find evidence of a crime. The judge will review the evidence and, if satisfied, issue the warrant, allowing the officer to search a specific location for the specified evidence.
Obtaining a search warrant typically takes a few hours to a few days, depending on the circumstances and the availability of a judge to review and approve the warrant application.
Warrant
First, you cannot obtain a search warrant. Police and prosecutors can, but only if they have enough evidence that there has been a crime, and that searching might solve it. Search warrants must be issued by judges.
Absolutely!!! It is called helping to secure our borders and country!!! Would you want a vehicle full of explosives intercepted at the border because of a warantless border search or would you rather have it make it through and to its target because the customs agents did not have sufficient probable cause to search the vehicle or enough information to obtain a search warrant?