It then predicts growth above 3 percent annually for the next several years if the administration’s economic policies are enacted. The Fed, the budget office and others all see growth falling below 2 percent annually in that time. By 2030, the administration predicts the economy will be more than 15 percent larger than forecasters at the budget office do.

Past administrations have also dressed up their budget forecasts with economic projections that proved far too good to be true. In its fiscal year 2011 budget, for example, the Obama administration predicted several years of growth topping 4 percent in the aftermath of the 2008 financial crisis — a number it never came close to reaching even once.

Trump officials had considered their projections to be a break from that trend, writing last year that they were the first administration on record “to have experienced economic growth that meets or exceeds its own forecasts in each of its first two years in office.” That turned out to be wrong: In the middle of last year, the Commerce Department revised its accounting of the 2018 growth rate downward, to well below the rate Trump officials had forecast. Their predictions were similarly off in 2019.

Robust economic growth rates are not the only area where the administration’s renewed optimism appears in its latest budget. It has also revised down its estimate of the interest the federal government would pay to borrow money over the next decade, based largely on the assumption that the Fed, which began cutting rates in 2019, would raise them only modestly again over the next 10 years. The changes in rate assumptions reduce budget deficits by $1.5 trillion over the course of the decade, according to the administration’s projections.

Essentially, administration officials are contending that rising levels of debt in the United States will not drive up borrowing costs, as many conservative economists have long warned, at least for the next several years. They also believe, a rarity among economists, that a sustained stretch of 3 percent growth would not push the Fed to raise interest rates. Administration officials do not directly control Fed policy, but in a companion document to the budget, the officials wrote that federal borrowing costs would stay low “as U.S. debt continues to be in high demand because it is a safe haven for savings amidst global turmoil.”