While there are several advantages to registering a trademark, conspicuously absent from the list of benefits is the ability to acquire a trademark. You acquire a mark in the United States by using it, not by registering it. Registration, then, has everything to do with enhancing the rights already granted by virtue of using the mark. However, many of these advantages are only available to marks that are registered on the Principal Register as opposed to those registered on the Supplemental Register


See Also... 

Benefits of Registration (Principal vs. Supplemental Registers) 

How do I Obtain a Trademark?