American Thinker has article out yesterday about unobligated balances and that president has the authority to use that unspent money because I guess congress had already appropriate it.
While President Trump is correct to remain committed to building a border barrier and has asked all Cabinet agencies for wall funding, he can fund the entire barrier without having to declare a national emergency. Instead, he can draw full funding for a complete border barrier from unobligated balances. Unobligated balances “are the amounts of budget authority that have not yet been committed by contract or other legally binding action by the government.” Former senator Tom Coburn described unobligated balances as “essentially money for nothing.” While in 2012 there was an estimated $687 billion in unobligated balances, unobligated balances in federal and trust funds in FY 2019 is estimated to be a whopping $1,156,136,000,000 (See Table 1 on page 9). The total estimated unexpended end-of-year balance (i.e., the unspent balance including unobligated and obligated balances) for FY 2019 is $2,650,531,000,000.
There are two (main) forms of unspent money, that is “swept” up every year. I know this process from DoD contracting. They first sweep uncommitted (not on contract, failed contracts, or underspent contracts) in May/June, and then they try to get it committed before Sept. Then there is the final sweep in August/Sept where they do thier best to get the money pushed out the door, or on extension allowing it to be spent into the next GFY.
All this is based on the fact that office/project budgets are “use it or lose it”, that being if you don’t spend your budget, next year it gets cut by that much.
As to what this can be spent on, I am unsure of the limits of how far differently allocated monies can be repurposed.