The 4th Amendment and case law relevant to police power for arrests without a warrant
<p>The 4th Amendment states that</p>

<blockquote>
  <p>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.</p>
</blockquote>

<p>which, read literally, states conditions under which it is permitted to issue a warrant for arrest or search. It does not say that a person may not be seized or searched except if a warrant is issued, and I am not aware of any provision in the constitution that makes a warrant optional. Nevertheless, people are arrested by the police without them having first secured a warrant.</p>

<p>Is there some relevant case where it was decided that police have the power to seize people without a warrant? </p>

<p>"The touchstone of the fourth amendment is reasonableness". Ohio v. Robinette, 519 U.S. 33 (1996)</p>

<p>Carroll v. United States, 267 U.S. 132 (1925):</p>

<blockquote>
  <p>The Fourth Amendment denounces only such searches or seizures as are unreasonable, and it is to be construed in the light of what was deemed an unreasonable search and seizure when it was adopted, and in a manner which will conserve public interests as well as the interests and rights of individual citizens.</p>
</blockquote>

<p>Ker v. California, 374 U.S. 23 (1963):</p>

<blockquote>
  <p>The lawfulness of the arrest without warrant, in turn, must be based upon probable cause.</p>
</blockquote>

<p>United States v. Watson, 423 U.S. 411 (1976):</p>

<blockquote>
  <p>The cases construing the Fourth Amendment thus reflect the ancient common law rule that a peace officer was permitted to arrest without a warrant for a misdemeanor or felony committed in his presence as well as for a felony not committed in his presence if there was reasonable ground for making the arrest</p>
</blockquote>

<p>A very simplified parsing of the Fourth Amendment is "searches and seizures must be reasonable, and warrants must be specific (as opposed to <a href="https://en.wikipedia.org/wiki/Warrant_(law)" rel="noreferrer">general</a>)".</p>

<p>Dawn's last citation leads to the foundation of arrest without warrant. United States v. Watson, 423 U.S. 411 at 418 in dissent cites Wilgus <em>Arrest without a Warrant</em> 22 Mich L. Rev 541, which lists early (American) cases where the question has been raised at the state level (referring to state analogs of the 4th amendment). In some instances (North v. People, 139 Ill. 81, 104) it is pointed out that there is are statutory empowerments to arrest without warrant: "an arrest may be made by an officer or by a private person without warrant...". Even in lieu of such provisions, in Wakely v. Hart (1814) 6 Binn. (Pa.) 316 the court takes a "we can do what isn't prohibited" stance, saying "But it is nowhere said, that there shall be no arrest without warrant". In Holley v. Nix and Clute (3 Wend. 350) the proposition that "a felon can in no case be arrested without warrant, when there is time to obtain one" is rejected, citing a common law understanding that "if a felony has in fact been committed by the person arrested, the arrest may be justified by any person without warrant". The Germanic law underpinning seems to be that literally <em>anyone</em> may, indeed must make an arrest, with the lynch mob being at the less-civilized end of the continuum of detaining miscreants, and acting under the authorization of a justice of the peace being at the more-civilized end. (If there was no felony, those who follow the hue and cry would be liable, and the warrant protects those who arrest in error). </p>

constitutional-law search-and-seizure case-law arrest