Dick Cheney is quoted as saying, “Reagan proved that deficits don't matter." But the full quote was “Reagan proved that deficits don't matter. We won the mid-term elections, this is our due." What Cheney meant was that the deficit didn't matter to the electorate, which voted in Republicans.
More recently (2017), Paul Krugman wrote an opinion piece "Deficits Matter Again". The argument (which is pretty standard for economists) is that the wisdom of deficit spending depends on the economic cycle. If stuck in a recession, it can be helpful to give the economy a boost. But few economists would agree that deficit spending is a good long-term policy. Here is more from Krugman: "What changes once we’re close to full employment? Basically, government borrowing once again competes with the private sector for a limited amount of money. This means that deficit spending no longer provides much if any economic boost, because it drives up interest rates and “crowds out” private investment."