WASHINGTON (Reuters) - When President Donald Trump proposes his 2020 federal budget on Monday, official Washington will likely have a quick look, shrug and move on, marking another stage in the quiet decay of the U.S. government’s traditional policy-making processes. There was a time when the release of the president’s budget was a red-letter day on the calendar of Washington wonkery, with policy experts and fiscal hawks delving into spreadsheets and expounding upon new spending plans and the national debt. But the hoopla of budget day is gone, a relic of a time when politics were less polarized, the federal...