act retroactively

基本解释

If Congress does act to retroactively reinstate the donation rule, the gift will be excluded from income just as under the pre-2012 rule.
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The act of retroactively canceling insurance is called rescission.
NPR: Insurers Revoke Policies To Avoid Paying High Costs
But in Hamdan, the high court held that the 2005 act did not apply retroactively, so that habeas proceedings already under way could continue.
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