There is no such thing as Marshall Law... unless you mean Marshal Dillon from Gun Smoke.
Or are you referring the speaker of the House of Representatives referring to Martial Law on the Congress until the bill is past.
If it is the first (Marshall Law) you should watch less television. If it is the second (Martial Law) the comment made by the speaker is very ignorant, or had about as much seriousness as James Trafficant and his "Beam Me up Mr. Speaker" comments he used to make.
Martial Law:
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Given the almost limitless authority these precedents provide you to use military forces for civilian law enforcement purposes within the United States however, it hardly seems necessary to address the nature of martial law.(77) Additionally, the precedents in this area are less well established -- apparently, there have been only two occasions where a president has formally declared martial law, both by President Lincoln.(78) On September 24, 1862, President Lincoln declared disloyal persons throughout the United States subject to martial law. He later placed the Commonwealth of Kentucky under martial law on July 5, 1864.(79)
Nevertheless, to give complete coverage to the issues which you raised, we present the following analysis.
While no federal statutes appear to define martial law, one section of the Code of Federal Regulations ("CFR") -- 32 CFR 501.4(80) -- makes four points about martial law:
First, federal troops are normally deployed domestically without a declaration of martial law.(81) "It is unlikely that situations requiring the commitment of Federal Armed Forces will necessitate the declaration of martial law."
Second, the "law of necessity" undergirds the implementation of martial law. "When Federal Armed Forces are committed in the event of civil disturbances, their proper role is to support, not supplant, civil authority. Martial law depends for its justification upon public necessity. Necessity gives rise to its creation; necessity justifies its exercise; and necessity limits its duration. The extent of the military force used and the actual measures taken, consequently, will depend upon the actual threat to order and public safety which exists at the time."
Third, declarations of martial law are not limited to the President. "In most instances the decision to impose martial law is made by the President, who normally announces his decision by a proclamation, which usually contains his instructions concerning its exercise and any limitations thereon. However, the decision to impose martial law may be made by the local commander on the spot, if the circumstances demand immediate action, and time and available communications facilities do not permit obtaining prior approval from higher authority (Sec. 501.2). Whether or not a proclamation exists, it is incumbent upon commanders concerned to weigh every proposed action against the threat to public order and safety it is designed to meet, in order that the necessity therefor may be ascertained."
Fourth, the rules of conduct for citizens are merely announced by the military and are immediately effective. "When Federal Armed Forces have been committed in an objective area in a martial law situation, the population of the affected area will be informed of the rules of conduct and other restrictive measures the military is authorized to enforce. These will normally be announced by proclamation or order and will be given the widest possible publicity by all available media. Federal Armed Forces ordinarily will exercise police powers previously inoperative in the affected area, restore and maintain order, insure the essential mechanics of distribution, transportation, and communication, and initiate necessary relief measures.
after that comment. 