Petitioner is a practitioner registered to practice before the United States Patent Office. He has not been admitted to practice law before the Florida or any other bar. Alleging, among other things, that petitioner 'is engaged in the unauthorized practice of law, in that although he is not a member of The Florida Bar, he nevertheless maintains an office * * * in Tampa, Florida, * * * holds himself out to the public as a Patent Attorney * * * represents Florida clients before the United States Patent Office, * * * has rendered opinions as to patentability, and * * * has prepared various legal instruments, including * * * applications and amendments to applications for letters patent, and filed same in the United States Patent Office in Washington, D.C.,' the Florida Bar instituted these proceedings in the Supreme Court of Florida to enjoin the performance of these and other specified acts within the State. Petitioner filed an answer in which he admitted the above allegations but pleaded as a defense 'that the work performed by him for Florida citizens is solely that work which is presented to the United States Patent Office and that he charges fees solely for his work of preparing and prosecuting patent applications and patent assignments and determinations incident to preparing and prosecuting patent applications and assignments.' Thereupon, the court granted the Bar's motion for a summary decree and permanently enjoined the petitioner from pursuing the following activities in Florida until and unless he became a member of the State Bar:
'1. using the term 'patent attorney' or holding himself out to be an attorney at law in this state in any field or phase of the law (we recognize that the respondent according to the record before us has already voluntarily ceased the use of the word 'attorney');
'2. rendering legal opinions, including opinions as to patentability or infringement on patent rights;
'3. preparing, drafting and construing legal documents;
'4. holding himself out, in this state, as qualified to prepare and prosecute applications for letters patent, and amendments thereto;
'5. preparation and prosecution of applications for letters patent, and amendments thereto, in this state; and
'6. otherwise engaging in the practice of law.'
The Supreme Court of Florida concluded that petitioner's conduct constituted the unauthorized practice of law which the State, acting under its police power, could properly prohibit, and that neither federal statute nor the Constitution of the United States empowered any federal body to authorize such conduct in Florida. 140 So.2d 587.
In his petition for certiorari, petitioner attacked the injunction 'only insofar as it prohibits him from engaging in the specific activities * * * (referred to above), covered by his federal license to practice before the Patent Office. He does not claim that he has any right otherwise to engage in activities that would be regarded as the practice of law.' We granted certiorari, 371 U.S. 875, 83 S.Ct. 148, 9 L.Ed.2d 113, to consider the significant, but narrow, questions thus presented.
We do not question the determination that under Florida law the preparation and prosecution of patent applications for others constitutes the practice of law. Greenough v. Tax Assessors, 333 U.S. 486, 67 S.Ct. 1400, 91 L.Ed. 1621; Murdock v. Memphis, 20 Wall. 590, 22 L.Ed. 429. Such conduct inevitably requires the practitioner to consider and advise his clients as to the patentability of their inventions under the statutory criteria, 35 U.S.C. §§ 101-103, 161, 171, as well as to consider the advisability of relying upon alternative forms of protection which may be available under statute law. It also involves his participation in the drafting of the specification and claims of the patent application, 35 U.S.C. § 112, which this Court long ago noted 'constitute(s) one of the most difficult legal instruments to draw with accuracy,' Topliff v. Topliff, 145 U.S. 156, 171, 12 S.Ct. 825, 831, 36 L.Ed. 658. And upon rejection of the application, the practitioner may also assist in the preparation of amendments, 37 CFR §§ 1.117-1.126, which frequently requires written argument to establish the patentability of the claimed invention under the applicable rules of law and in light of the prior art. 37 CFR § 1.119. Nor do we doubt that Florida has a substantial interest in regulating the practice of law within the State and that, in the absence of federal legislation, it could validly prohibit nonlawyers from engaging in this circumscribed form of patent practice.