fiscal multipliers are about 1. The government simply becomes another company with a specialized product mix and pricing policy.
Employing the apparently common terms "guns & butter" and "swords & plowshears"; an untaxed economy w/o government would have some AD, and some AS. That AS would be relatively efficient and cost-effective, so that the AS curve would be lower.
With taxes and government, taxes increase costs, making AS less efficient & less cost-effective, so that the AS curve becomes higher. But, the
magnitude of AD (measured in monetary terms) remains more-or-less the same. Thus, one main effect of taxes is simply to make the economy less efficient, less cost-effective, with a higher AS curve. That will tend to increase prices, and reduce quantities.
Now, the "Q" measured along the x-axis is the
magnitude of aggregate output. In detail,
Q is a (huge)
vector, whose (myriad) individual components are the (myriad) individual quantities of the (myriad) individual products (goods & services) transacted in the economy, per year:
Q = [apples, bananas, cherries, dates, exasketches, figs, garage-door-openers, hamburger, ice-makers, jewelry, kudos, lemons, mangos, nectarines, oranges, peaches, quality-assurance-certifications, raisins, steel, tapioca, Union-training-certifications, Volkswagons, watches, x-ray-machines, yams, zippers....]
|Q| = "Q"
Likewise, the "P" measured along the y-axis is the
magnitude of aggregate price-levels. In detail,
P is a
vector, matching the above, representing the prices of all those quantities, in each year:
P = [$1/lb., $0.50/lb., $2/lb., $3/lb., $4 ea., $5/lb., $6 ea., $7/lb., $8 ea., $9K ea., $0.10/lb., $0.11/lb., $1.20/lb., $1.30/lb., $1.40/lb., $1.50/lb., $1.60/lb., $170 ea., $1.80/lb., $190/ton, $20/lb., $2100 ea., $22K ea., $23 ea., $24K ea., $0.25/lb., $0.26 ea....]
|P| = "P"
On the AD & AS chart, only the
magnitudes "P", "Q" are plotted; but the
other main effect of taxes & government, is to
change the mix of products transacted, in the economy, per year. Over-simplistically, "butter becomes guns" & "plowshears become swords" (and "Fords become Sherman-tanks"). Mathematically, the
magnitudes "Q", "P" don't change much; but, as the
mix of products changes, those vectors "rotate" (in a huge dimensional mathematical space). Over-simplistically, the economy "rotates", along a production-possibility-frontier (PPF), from "butter" towards "guns".
Inexpertly, i identify two main effects of taxes & government:
- increasing costs, raising the AS curve
- transforming the economy, changing the product-mix, "rotating" the "Q" axis, along a PPF, away from whatever private-sector products are dis-incentivized through taxes, towards whatever Public-sector products are incentivized through government expenditures
the magnitude of the rise in the AS curve reflects the economic inefficiencies, of
de facto employing government force, to "twist arms" and coerce & compel people, to spend their money, on what the Public-sector wants (
via taxes), instead of on what they would have wanted themselves. "Government Guns" in the market-place doesn't increase the amount of money available, or increase spending (AD). Instead, Government "gets in the way", "picking everybody's pocket". The more Government imposes on people, the higher the tax burden, and the higher the AS curve, reflecting that economic inefficiency. Meanwhile, the economy "shifts" away from the private-sector, to the Public-sector, along a PPF, of roughly constant
magnitude.
For Public goods, private incentives, in the private-sector economy & market-place, do not reflect the collective Public interest.
Cp. Prisoner's Dilemma, nobody privately has any incentive to cooperate, but they all do collectively. For such Public goods, private-sector market forces will "mis-orient" the economy, "pointing" the
P,Q vectors in socially inefficient "wrong" directions. When, then, collective action & bargaining is beneficial, taxes & government can "re-orient" the economy, "re-pointing"
P,Q towards (enough) more "guns, swords, & tanks" to be beneficial, in net (pros less cons).