From Infogalactic: the planetary knowledge core

The Flag Protection Act of 2005 was a proposed United States federal law introduced by Senators Hillary Rodham Clinton and Robert Bennett. The law would have outlawed flag burning, and called for a punishment of one year in jail and a fine of $100,000.[1][2]

According to the nonpartisan Congressional Research Service, the act was summarized as such:

Amends the federal criminal code to revise provisions regarding desecration of the flag to prohibit: (1) destroying or damaging a U.S. flag with the primary purpose and intent to incite or produce imminent violence or a breach of the peace; or (2) stealing or knowingly converting the use of a U.S. flag either belonging to the United States or on lands reserved for the United States and intentionally destroying or damaging that flag.[3]

Since the law was not passed nor considered by the United States Congress, its constitutionality was not challenged by the Supreme Court; the bill was never assigned to committee.[4] However, the bill's language was designed so as to prohibit the desecration of a flag when the intent was found to be a threat to public safety, the intention being that it would therefore not violate the First Amendment and not be declared unconstitutional.[5]

Both co-sponsors of the bill voted against the most recent Flag Desecration Amendment of 2006.