I was thinking about this situation last night.
Let’s say they pass a budget that includes a discretionary increase of 5% over last year.
Can’t Trump order the departments to spend 10% less than last year? I mean, is he obligated to spend the money is he?
The Executive is NOT obligated or bound to spend as much as the Congress allocates.
Unless the budget law says funds “must” be expended on certain items, as is the case with entitlements.
Trump can have his cabinet cut 20% across the board in every discretionary dept. Though there are some personnel actions that require Congressional approval...like refusing to deal with Unions, benefits, mass layoffs etc.
But Trump can get around those by insisting on wording changes in any/every new budget and can win them easily in trade for something the Republican commies want.
Like airports in Alaska.