At least I've wondered about it. I'm not bashing conservatives who voted for him, but I have always insisted he was in no way a fiscal conservative, not in his first term anyway.
A couple things:
First, I think we (all of us generally) have a tendency to overstate the President's influence on spending. I'm not saying that he has none but the lawsuits seeking to compel Trump to spend money that was appropriated by Congress illustrate that this simply isn't a decision that a President can make on his own.
Second, I see so many political posts (from both sides) that run with this. Democrats typically blame Reagan and Supply Side Economics to which my answer is that the HoR was controlled by Democrats for the entirety of Reagan's tenure and Constitutionally spending measures can ONLY originate in the HoR so to try to hold Reagan solely accountable for spending under his watch is disingenuous at best. Additionally, debt as a percentage of GDP was a little over 30% when Reagan took office in 1981 and a little under 50% when he left office in 1989 and both of those are sustainable.
Then I've seen similar claims from the left that "Clinton balanced the budget", well . . . The debt was a little under 63% of GDP when Clinton was elected in Q4, 1992 and when he took office in Q1, 1993. It continued it's gradual rise and peaked at 65.31% in Q2, 1995 THEN began a slow decline that bottomed out at just over 54% immediately prior to 9/11. Giving Clinton 100% of the credit for debt reduction that didn't start until AFTER the Republicans took over congress in the 1994 election is again, disingenuous at best.
Even after that, the debt "only" grew from just over 54% immediately prior to 9/11 to around 64% right before the 2008 credit bubble crash and recession. It wasn't until then that the debt just got completely out of hand. It spiked to over 73% in Bush's last quarter in office and over 77% in Obama's first. By the end of 2010 it had risen to over 90% then Republicans won the 2010 mid-term elections but unlike 1994-2000 when we had a Democratic President and a Republican Congress, the Debt continued to rise. By the last quarter of Obama's tenure (Q4, 2016) it was up to almost 105% of GDP.
Getting to your comment about Trump here well, when he took over (Q1 2017) the debt was just under 103% of GDP and in the first quarter of 2020 (immediately prior to COVID) it had "only" grown to just under 107%. That certainly isn't good but 1% annual growth isn't awful either, at least by comparison. In Obama's tenure it grew by about 28% (77% to 105%) in eight years which is 3.5% per year. Not that I'm blaming that entirely on Obama because I'm not. He shouldn't get 100% blame for the increase any more than Clinton should get 100% credit for the decrease.
As I see it, the problem is twofold:
First, every time some calamity comes along we spend a boatload of cash based on Keynesian principles to prop up the economy. The two most recent are the 2008 crash and COVID in 2020:
- Debt as a percentage of GDP rose from ~64% of GDP in Q2, 2008 to ~88% of GDP two years later in Q2, 2010
- Debt as a percentage of GDP rose from ~107% of GDP in Q1, 2020 to ~120% of GDP two years later in Q1, 2022
Those two rapid increases cover the bulk of the increase since the debt was last what I would consider sustainable right before the credit bubble crash. From then to now it grew from ~64% to ~122%, an increase of 58%. 24% of that was credit bubble and 13% was COVID. Cumulatively that is 37%.
The second problem is that Milton Keynes himself suggested that governmental expenditures rise in downturns to stimulate the economy and fall in booms. The second half of that simply hasn't happened at all. The debt shot up for the credit bubble but never got reduced once things got going again and continued to drift upward until COVID then shot up again. Post-COVID it did drop from a high of ~133% but only to a low of ~116% and it has been drifting higher since then.