Jamaldog87 - rest assured the US Marshalls will not be deputizing you any time soon. As a retired State LEO we worked with the FBI/ATF/USMS/Customs and IRS on multiple large investigations involving drugs/smugling/gambling etc. These are all very highly trained and (bless their hearts) beaurocratic controlled agencies and the last thing they want is non-LEO running around "deputized"!
Read the posts by JBlk and GaryG. They are very informative and accurate-BTW- thanks for the good info. To bring the Posse Comitatus law down to a local level a tr or two ago some nut went off his rocker in S. AL and started killing family and random citizens w/ a semiauto rifle(NOT AN ASSUALT RIFLE @*&&^%* CNN) A local sweet old guy tried to stop him, ramming his truck and was killed despite his heroic efforts. The Military Police from Ft Rucker AL responded to aid the local/CO and State LEOs and played an active role, after the shooting was finally stopped, until civilian LEOs took over. It was reported in the news that their actions were a violation of the Posse Comitatus Act- no further reports were made. Some LT may have got his ass chewed, but in that situation (been there done that-have the Tee shirt)- who cares about a 1800 era law when someone is shooting at you? IMHO-Good on them!