The US hasn't had a real balanced budget in much longer than that. During the Clinton era the balance was achieved in part by stealing from Social Security by keeping the surplus inflows and pretending there's a magic locked Social Security box with trillions of dollars in it (which are really IOUs backed by the Fed's ability to debase the future for past over-spending). We similarly treated as 'surplus' tax revenue that should have been set aside for future higher Medicare costs (which back then we knew full well were coming) and is now burning a massive hole in the present budget.

The Clinton years were the twilight of the fantasy of abusing inbound entitlement tax flows for spending in the present and ignoring the future. That government spending party trick - kicking the can down the road - is now exhausted on a normalized basis, so we're rapidly heading toward perma QE as the only solution remaining other than very high taxation across all major income groups.

Can someone explain to me the negative consequences of running a deficit? Countries aren’t people. They don’t die. As long as countries are willing to lend us money and the US can service the debt, what does it really matter if the national debt is multiples of the GDP?

There are no real negative consequences. Fiscally conservative people want people to think there are because it's a way to counter government spending with an argument that makes sense on the surface, despite the fact that the argument is completely wrong if you spend a few minutes thinking about it.

We will spend $479 Billion in interest on the national debt in 2020.

That's >22 NASAs-worth of money, if you care about space exploration. It could be roads or high speed trains or education or healthcare or whatever you care most about.

Instead it's going towards paying interest on debt incurred for cheap political wins in the past...

That doesn’t matter, because it’s not a binary choice — that is, we don’t not spend money on NASA because of the deficit.