Tighten Washington's Belt Act of 2010

Tighten Washington's Belt Act of 2010 - Requires the Office of Management and Budget (OMB), within 15 days after the end of a session, to issue a Discretionary Sequestration Report and, if in such report OMB estimates that any sequestration is required, the President to issue an order (effective on issuance) fully implementing without change all such sequestrations.

Requires the Congressional Budget Office (CBO), within 10 days after the end of session, also to issue a Discretionary Sequestration Report.

Subjects to permanent cancellation any budgetary resources sequestered from any account, except those in special fund accounts or offsetting collections sequestered in appropriation accounts. Applies the same percentage sequestration to all programs, projects, and activities within a budget account.

Requires the Comptroller General, upon request of the congressional budget committees, to report to Congress and the President on the extent to which each such issued presidential order or OMB or CBO report complies with all of the requirements contained in this Act, either certifying that the order fully and accurately complies with such requirements or indicating the respects in which it does not.

Requires Discretionary Sequestration Reports for each of FY2011-FY2015 to set forth estimates for: (1) the applicable discretionary spending limits; (2) the new budget authority and the breach, if any; (3) the sequestration percentages necessary to eliminate the breach; and (4) the level of enacted sequesterable budget authority, and resulting estimated outlays to be sequestered for each account.

Requires the OMB report to explain: (1) any differences between OMB and CBO estimates for any breach and any required discretionary sequestration percentages; and (2) differences in the amount of sequesterable resources for any budget account to be reduced if such difference is greater than $5 million.

Establishes discretionary spending limits for FY2011-FY2015.

Sets forth sequestration enforcement mechanisms.

Subjects all discretionary budget authority to such sequestration procedures, except: (1) benefits and compensation provided to active duty military and to veterans defined as discretionary spending; (2) provisions of discretionary spending legislation the President and Congress designate as emergency requirements; and (3) salaries or other expenditures that may not be reduced on account of constitutional requirements.