So a few things are wrong with this idea:
1. We are not on the gold standard anymore.
2. In our economy there are funds that are just lying around because no one is using them.
3. Even if the economy was better and the private sector were not hoarding cash and if they were instead fully utilizing all resources, there is no fixed 'pot of gold'. The amount of funds in circulation are completely driven by demand. So, if the government wants to spend more money, they don't 'take it' from the private sector. They just spend the money and US bonds are issued - with no effect on the amount of resources whatsoever.
But people don't seem to get this. Especially conservatives.
But as I've been trying to convince people for years, the reason that conservatives don't get it is because mainstream economists don't get it, and they keep teaching bullshit... like crowding out. I keep teaching bullshit like crowding out too, because I'm virtually forced to - but I also try my best to say in a very professional way, "this is bullshit".
And then the brainiacs at the Congressional Budget Office say things like this (from 2009):
"ARRA's [Obama stimulus] long-run impact on the economy will stem primarily from the resulting increase in government debt. To the extent that people hold their wealth in government securities rather than in a form that can be used to finance private investment, the increased debt tends to reduce the stock of productive private capital."I have bolded that last sentence for you. What it is saying is that crowding out will happen, but what it also implies is that crowding out will happen only under certain assumptions: "To the extent that people hold their wealth in government securities rather than in a form...." implies that there is an either/or situation. The CBO is making this assumption, which I just told you is false - and that every central banker will tell you, is false. There is not either/or situation between bonds or savings that businesses can use. Businesses don't finance their investment from some fixed pool of money.
Can you imagine if a business went to a bank for a loan, made the business case for the loan (which was a good one), but then the bank says, "Oh I'm so sorry sir, but we've plum run out of money. I mean, we had some, but unfortunately the government sold so many treasury bonds that we now have none left." I mean - seriously? Has this ever happened? No, it hasn't. Do you know why it hasn't? Because loans are not made from some fixed pot of gold. Loans are made based on risk and return and the business case, and that's it. Banks never 'run out of money'. That's what the Federal Reserve does - ensures that banks have the money they need to do business.
Having said all this, is it possible that in some cases government spending influences business incentives to a degree that might cause less private investment. Yes, probably. But, that's not what the mainstream theory says. The mainstream theory is crowding out occurs because there is a fixed pot of gold so banks won't have resources to make loans, and interest rates will rise so businesses won't want to borrow, and taxes will rise in the future so that the average Joe will hoard his cash that would otherwise go to US businesses. All of that theory was born at a time when we actually did have a fixed pot of gold. But today, all of that, is bullshit.