S.3930, the Military Commissions Act of 2006, contains various sections legalizing past actions of the government, such as this section:
(2) RETROACTIVE APPLICABILITY- The amendments made by this subsection, except as specified in subsection (d)(2)(E) of section 2441 of title 18, United States Code, shall take effect as of November 26, 1997, [...]
The Constitution explicitly prohibits ex post facto legislation, i.e., passing laws that are effective retroactively. The primary intent is to prevent Congress from passing a law to make something a psrson did in the past, which was legal at the time, illegal and punishable. This is one of the requirements for Rule of Law; the people must have
the ability to determine the legality of their actions.
However, it is also important that Congress not be able to retroactively make the actions of government legal (i.e., a retroactive grant of additional power to the government). If Congress can do that, there is effectively no legal control on the power of government other than the Constitution itself. The executive branch can then get away with ignoring laws at its convenience, and if caught doing so, asking Congress to retroactively change those laws.
It is unclear to me whether the Federal courts would interpret the prohibition of ex post facto legislation as prohibiting retroactive grants of power to the government. If S.3930 becomes law, I would hope that the ACLU would challenge its Constitutionality at least partly on that basis.
Note that by comparison, I am not opposed to a law that retroactively makes actions of private (non-government) parties legal, because this does not expand the powers of goverment, but rather removes restrictions on the rights of the people.
Ex Post Facto legislation
S.3930, the Military Commissions Act of 2006, contains various sections legalizing past actions of the government, such as this section:
The Constitution explicitly prohibits ex post facto legislation, i.e., passing laws that are effective retroactively. The primary intent is to prevent Congress from passing a law to make something a psrson did in the past, which was legal at the time, illegal and punishable. This is one of the requirements for Rule of Law; the people must have
the ability to determine the legality of their actions.
However, it is also important that Congress not be able to retroactively make the actions of government legal (i.e., a retroactive grant of additional power to the government). If Congress can do that, there is effectively no legal control on the power of government other than the Constitution itself. The executive branch can then get away with ignoring laws at its convenience, and if caught doing so, asking Congress to retroactively change those laws.
It is unclear to me whether the Federal courts would interpret the prohibition of ex post facto legislation as prohibiting retroactive grants of power to the government. If S.3930 becomes law, I would hope that the ACLU would challenge its Constitutionality at least partly on that basis.
Note that by comparison, I am not opposed to a law that retroactively makes actions of private (non-government) parties legal, because this does not expand the powers of goverment, but rather removes restrictions on the rights of the people.