4th Amendment question

[D. Scarlatti]

Here is how the 4th Amendment to the U.S. Constitution reads:

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.

Let's call the green portion "the Unreasonableness Clause" and the red portion "the Warrants Clause."

Setting aside anything you might know about police procedure, caselaw, or Law & Order episodes, do you think that:

1) The Amendment requires a warrant for searches and seizures;
2) The relationship between the two clauses is "unclear";
3) If 2), why.