> There must be some consequence to increasing the supply of money.

MMT holds to the orthodox monetary view that inflation/deflation result from expansion/contraction of money supply relative to output. MMT, despite its name, is quite orthodox in monetary theory.

Where it is (somewhat, though most orthodox voices I think would concede this point if cornered and unable to talk around the question) unorthodox in description is in theory of government finance, as it holds that fiscal constraints are a fiction (for a government operating in its own fiat), and that the only real constraints on government spending and its relation to taxes are not fiscal limitations of a finite purse but the monetary effects of money creation by spending and money destruction by extraction via taxes, etc.

But the real conflict between MMT practitioners and orthodox economics doesn't even seem to be on the empirical, descriptive elements of economic theory, but prescriptive/normative elements of policy recommendations made by adherents to the theory.

MMT does not say that you can't cause inflation by increasing money supply.

It does say that the government that controls the currency (monetary sovereignty) never has to default.

I think people may be mixing up the increasing popularity of MMT with the idea that we have been "pumping money into the economy" for years without the official measures of inflation ticking up much, at least until very recently.

I don't think the average person buying cars, trying to rent/buy housing, or send their kids to college would agree with the official narrative of low inflation however.

I understand MMT is the increase in money supply is accompanied by an increase in taxation and by taking the money back out of the economy slows inflation.

I think the caveat is that politicians can supply money into the economy (increase their chances of re-election), but will be reluctant to raise taxes in an effective way (to not decrease their chances of reelection).

Unless the government burns or locks away the money it taxes - in which case all effects of MMT are muted - it is going to just lead to inflation from government expenditures. There is no way to escape the price impact of increasing the money supply, as prices are always set by supply and demand.

MMT is one of those persuasions that can only exist in America, same as Libertarianism on the other political end.

In any non-American 'monetary sovereign' country, printing too much money will crash the exchange rates (this is not merely a consequence of inflation - some of the processes involved are independent). It's a slightly different casual mechanism than the neoclassical one, but still the result is a de facto government default.

The USA however holds the world's reserve currency, and the normal restraints indeed don't apply anywhere as much. This however does not mean there are no restraints. Fortunately the country has never gone full MMT, so we'll never find out empirically.

yes, the consequence is; those who are more easily able to accumulate the money, will still hoard and stash all the excess.