In any case, Reason Magazine, something I used to subscribe to way back in my libertarian days, has published a fairly strong assessment of that claim.
The essay is too long to be reasonably condensed into a forum post, so I'm going to break it up into three.
https://reason.com/2020/10/04/the-case-against-trump-donald-trump-is-an-enemy-of-freedom
Part One: The Trillion-Dollar Tax
The Trillion-Dollar Tax
"Keep your eye on one thing and one thing only: how much government is spending," economist Milton Friedman famously said during the Carter administration. "Because that's the true tax."
Under Trump's signature, even before the coronavirus, the sticker price on that annual levy was jacked up by almost $1 trillion.
Federal spending under Barack Obama went from $2.98 trillion in George W. Bush's last full fiscal year of 2008 to $3.52 trillion in the stimulus-weighted fiscal year of 2009, an increase for which Obama and the Democratic-controlled 111th Congress deserve the lion's share of responsibility. Since the 44th president's last full fiscal year of 2016 saw expenditures of $3.85 trillion, we can say that during his two terms of office—which included a major federal response to an economic crisis—annual spending went up by around $900 billion.
Trump matched that increase in just one term, before his own crisis hit.
Fiscal 2017 featured spending of $3.98 trillion, with most of the $140 billion increase over the previous year coming under Trump's sharpie. Then things really took off—$4.11 trillion in 2018, $4.45 trillion in 2019, and a whopping $4.79 trillion destination at the halfway point of fiscal 2020. And then came the pandemic.
Discretionary spending—meaning that part of the budget (roughly one-third) requiring explicit congressional approval, as opposed to "mandatory" items such as Social Security, Medicare, and Medicaid—never topped $1.2 trillion during Obama's second term. Trump's wholly owned, pre-virus budgets saw the discretionary portions rise from $1.28 trillion to $1.36 trillion to $1.44 trillion.
tl:dr version: Trump profligate spending has made a mockery of Republican claims to conservatism. Lest anyone be confused, it is reiterated several times that this is not counting 2020; these are pre-pandemic numbers. In his first year alone, Trump increased spending more than Obama had increased it over his entire eight years.
