(2) Exercise of powers and authorities Any emergency power or authority made available under a provision of law specified pursuant to section 201(b) may be exercised pursuant to a declaration of a national emergency for 30 days from the issuance of the proclamation or Executive order (not counting the day on which such proclamation or Executive order was issued). That power or authority may not be exercised after that 30-day period expires unless there is enacted into law a joint resolution of approval under section 203 approving— (A) the proclamation of the national emergency or the Executive order