From the usac link:
10.28 Unsportsmanlike Conduct - Any participant who, in the judgment of the Chief Steward or the Director of Competition, is
guilty of unsportsmanlike conduct during a race meeting may be subject to any or all of the appropriate penalties in Rule 10.2.
Without limiting the generality of the foregoing, unsportsmanlike conduct shall include reckless and overly aggressive driving
endangering the safety of participants.

10.30 Assault or Battery - If any competitor or other persons during or in respect to a race meeting shall commit an assault or
battery, such person, so offending, shall at once be disqualified and/or excluded by the Chief Steward and reported to the
Director of Competition for consideration of further penalties.

10.32 Conduct Detrimental to Racing - Any participant who, in the judgment of the Director of Competition, the Executive
Committee, or the Board of Directors, is guilty of conduct detrimental to racing and/or to the United States Auto Club, on or off
the track, may be suspended and/or fined by the Director of Competition or the Board of Directors and/or the Executive
Committee.

10.3 Authority to Pronounce a Fine - The USAC Chief Steward shall have the authority to pronounce a fine up to $2,500 upon
any participant or member who violates any USAC rule. To this, the Director of Competition, the Board of Directors or the
Executive Committee may add further penalty.
A. The Director of Competition, the Board of Directors and/or the Executive Committee shall have the authority to levy a
fine not exceeding fifty thousand dollars ($50,000) against any participant or member who violates any USAC rule.

As I stated before, I am still a Stewart fan in spite of this incident and feel no action should be taken against Tracy (or Levi) as they had no hand in the incident. The people who posted about this being a PR positive for USAC are probably right. I saw the thing on TV this morning while I was looking for a weather report.