H.R. 3988 would amend the National Emergencies Act to limit to 30 days the duration of any national emergency declared by the President unless the Congress subsequently approves or extends the declaration. The bill also would require the President to report to the Congress periodically on the need for and status of declared emergencies. CBO cannot predict the number or timing of future declarations but expects that most would be approved by the Congress. Under H.R. 3988 emergency declarations could have a shorter duration than under current law. If that happens direct spending related to such emergencies would decline; CBO estimates any reduction in direct spending would be insignificant. CBO estimates that enacting the bill would not affect revenues. CBO has not estimated the bill’s effects on spending subject to appropriation. The bill contains no intergovernmental or private-sector mandates as defined in the Unfunded Mandates Reform Act.