According to the CBO baseline, mandatory spending in fiscal 2019 is now projected at $2.96 trillion; discretionary spending at $1.52 trillion; and net interest at $0.45 trillion.
In January 2009, before Barack Obama took office, projected mandatory spending in 2019 was $2.89 trillion; discretionary spending $1.39 trillion; and net interest $0.70 trillion. The rise in net interest is overwhelmingly the consequence of the burst of countercyclical deficits caused by the recession--and thus not Obama's responsibility.
The combination of changes in budgetary and economic assumptions and changes in legislation have thus raised fiscal 2019 spending by $0.20 trillion--rather less than 1% of GDP. Not all of those changes are the responsibility of Obama: I would say about 1/3 of them are, with the rest mostly being flaws in how CBO constructs it's current-law baseline estimates. But say they all are: then Obama has raised projected federal spending by something less than 1% in the ten-year medium run, and has lowered it in the long run relative to baseline as the ACA policies cumulate.
Thus I believe that any rational and reality-based look concludes that Obama has been good news for long-run federal spending restraint. And even an irrational, fantasy-based position cannot claim that Obama has raised projected federal spending by more than a small amount--a much smaller amount than either George W. Bush or Ronald Reagan.
The thing I think Paul finds most annoying about John is that there are no signs in the record that Taylor used his position as Undersecretary of the Treasury in the Bush administration to argue for spending restraint at all--and that now he is trying to shift responsibility for the spending increases set in motion by his president to Obama. You can think that the unfunded Medicare D is a good thing or a bad thing, but it is a Bush thing.