I found 'The Search and Seizure of Private Papers: Fourth
and Fifth Amendment Considerations' (1973) [1] a very interesting read, and draw from it heavily in the following... A more updated brief can be found under '' "Dearest Property": Digital Evidence and the
History of Private "Papers" as Special Objects of
Search and Seizure' (2013) [2]

You're right, and I mispoke, it's not a matter of free speech as it is a matter of ensuring the privacy and security of the individual. However I think it's incorrect to say that for the entire history of the United States they could search your person, house, papers and, effects. This is matter for the 4th and 5th not 1st, starting back with Boyd v United States in 1886, and has seen much movement and refinement in the last 40 years particularly;

The seizure or compulsory production of a man's private papers to be
used in evidence against him is equivalent to compelling him to be a
witness against himself, and, in a prosecution for a crime, penalty or
forfeiture, is equally within the prohibition of the Fifth Amendment.

Both amendments relate to the personal security of the citizen. They
nearly run into, and mutually throw light upon, each other. When the
thing forbidden in the Fifth Amendment, namely, compelling a man to be a
witness against himself, is the object of a search and seizure of his
private papers, it is an "unreasonable search and seizure" within the
Fourth Amendment.

U.S. Supreme Court
Boyd v. United States
116 U.S. 616 (1886)

'Boyd thus created a "zone of privacy that [could] not be invaded by the police through raids, by the legislators through laws, or by magistrates through the issuance of warrants.' (Warden v. Hayden, 387 U.S. 294, 313 (1967))

[T]here are some crimes, such, for instance, as murder, rape, robbery,
and house-breaking, to say nothing of forgery and perjury, that are
more atrocious than libelling. But our law has provided no paper-search
in these cases to help forward the conviction. Whether this proceedeth
from the gentleness of the law towards criminals, or from a
consideration that such a power would be more pernicious to the innocent
than useful to the public, I will not say. It is very certain that the
law obligeth no man to accuse himself; because the necessary means of
compelling self-accusation, falling upon the innocent as well as the
guilty, would be both cruel and unjust; and it would seem, that search
for evidence is disallowed upon the same principle. Then, too the
innocent would be confounded with the guilty'

-- Entick v. Carrington

The sanctity of papers was limited in Gouled in 1921, taken away more fully by Warden in 1967. What was once considered an unwarrantable intrusion into personal privacy, and compulsary self-incrimination, was now considered a reasonable trade-off against personal privacy and sanctioned "after fulfilling the probable cause and particularity requirements of the Fourth Amendment and after the intervention of 'a neutral and detached magistrate.'

In Katz v United States in 1967, In Katz the government introduced evidence of the petitioner's part of a telephone conversation to prove that he had transmitted wagering information by telephone in violation of federal law.87 The Court, while finding the particular search to be invalid since it was not authorized by a warrant, stated:

[I]t is clear that this surveillance was so narrowly circumscribed
that a duly authorized magistrate, properly notified of the need for
such investigation, specifically informed of the basis on which it was
to proceed, and clearly apprised of the precise intrusion it would entail,
could constitutionally have authorized, with appropriate safeguards, the
very limited search and seizure that the Government asserts in fact took
place.

"However, the utterances at issue in Katz were wagering information and thus would be classified as means and instrumentalities of a crime rather than as mere evidence. 2 Furthermore, Katz did not deal with private papers and thus offers little assistance in determining whether there are circumstances in which private papers should be immune from search and seizure."

Diaries, and even private communication, to the extent that they are not instrumentalities and means by which a crime is committed, have long been seen as deserving protection even against seizure with a warrant. "Diaries, for instance, give rise to important privacy interests, are not a substantial means of committing any offense, and need not be seized for the general enforcement of any particular law. Their seizure in whole or part should not be countenanced unless the contents sought to be seized can be described with such particularity that it is clear that privacy interests have already been compromised."

'The positive law has closed its eyes on history. Federal Rule of Criminal Procedure 41 flatly equates “documents, books, papers, any other tangible objects, and information.” The rule plainly contemplates “the seizure of electronic storage media” for “later off-site copying or review.” Today, federal agents may obtain warrants to seize and carry away entire troves of digitally stored private papers and peruse those files at remote locations, one by one. What the leading Whig polemicist denounced as an “abominable outrage,” what the common law condemned as a relic of the Star Chamber, and what no American legislature authorized for the first eighty years of Independence, has become standard law enforcement procedure.' [2]

[1] - http://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=11...

[2] - http://scholarlycommons.law.northwestern.edu/cgi/viewcontent...