Search and Serizure
Border patrol searching cars on the border. They don't need a warrant for border searches.
Police cant enter a house with out a search warrant.
This is what a search warrant looks like.
About the 4th
The fourth amendment is one of the most important amendment because it give the rights to the citizens and gives then privacy in their homes, cars and their effects. Police can't enter your house without a search warrant or enter your car. They are allowed if the police can see something illegal. They can if they have probably cause, reasonable cause.