In a time of serious war, how much power does the government have in the US

We aren’t in a time of serious war, even during the worst of the war on terrorism only something like 0.6% of the country was in the military, and an even smaller fraction of them were involved in the fighting (maybe 0.07% of the country was actually in Afghanistan or Iraq at any given time during the worst of the wars). I think we spent something like 1-2% of GDP a year at best on the war on terrorism (not including whatever military spending we would’ve spent anyway).

But with WW2 I think about 10% of the country was in the military, and GDP spending on war was probably a lot higher. I don’t know the number though.

So in a time of war, what powers does the US government have in working with the private sector to prepare for war? Can the US government nationalize industry, break contracts, dictate to private industry, forcibly recruit scientists, or things like that?

Can the government order factories ‘stop making consumer goods and start making military arms’?

Can the military tell patent owners of valuable military technology ‘we aren’t going to respect your patents, we are going to make the weapons ourselves and not pay you royalties to save on money’?

Can the government nationalize private industries w/o compensation? Can they draft scientists and engineers to work on military projects and military technology the way they draft soldiers to fight in the military?

Was any of this done in WW2?

The government can do all of that and did most of it in WWII. Except not quite as phrased because a combination of incentives and voluntary action made it unnecessary to actually use the force of law in most cases. As usual, the government can do whatever it can get away with.

Somewhere I have a newspaper clipping, letter to the editor. A guy wrote in bitching about the lack of sugar for his grapefruit. Grandmother ripped him a new one in another letter, about her sons being overseas.
I don’t think people would be so cooperative now. There would be court cases about car factories diverted to making tanks and gas rationing.

The US government rounded up American citizens and placed them in concentration camps during WW2 for no reason other than their Japanese heritage. 62% of these individuals were American citizens, not foreigners who happened to be in the country. They were rounded up using US Census data.

Harry S. Truman famously tried to effectively nationalize some steel plants during the Korean War. The Supreme Court then held that he wasn’t allowed to do this, though the decision apparently left unclear the precise limits on what the President’s office can do. Notably, the Supreme Court decision implied that the action might have been legal if Congress had specifically authorized the President to do so.

It’s been a long time since the US actually had a congressional declaration of war, but by precedents going back to the Roman Republic, a declaration of a state of war is held to authorize things that would be illegal in peacetime. The first is a national draft, which is a huge stick to hold over men of military age. Presumably scientists and engineers would prefer to serve in stateside research projects than overseas as infantrymen. As far as economic measures go, a combination of the federal government’s power to regulate interstate commerce and imports from abroad, along with having the government as a guaranteed customer, was enough to persuade industry to comply. Typically the government prints money, gets as many people as possible to trade the money back for long-term government securities, and pays for expenses with elevated taxes for years afterwards. The USA in its modern form has never been desperate enough to resort to summary measures to continue a war effort.

The Bill of Rights specifically prohibits eminent domain without just compensation; so, no, the government cant seize private property without just compensation.

At its peak, Federal spending was 46% of GDP during WW2 (in 1943) and Defense spending peaked at 37% of GDP in 1945 (in that year defense spending was 89% of the Federal budget.)

Some of your questions you’ll need SCOTUS cases to find out the clear boundaries, and some have never been rigorously tested in that venue so it’s mostly unclear. But some form of everything you mentioned has happened before. During WW2

Most of the interactions between the government and industry were a mixture of coercion/carrots being offered and occasionally Roosevelt would strike with executive power. A good example would be the relationship between the government and labor unions. The CIO and AFI for example (the two largest unions at the time) and most other unions agreed to a no-strike pledge for the duration of the war. This meant no more union-wide strikes and no more local shop leaders striking. Instead, the government managed a type of arbitration to resolve disputes that generally kept wages for union workers consistently moving upward throughout the war. However because of general controls on wages and the fact that even with the arbitration salary increases worker pay did not increase faster than inflation. In response a lot of employers started offering vacation hours and other benefits to increase compensation through non-cash means.

However, John Lewis, who headed the CIO and who was anti-Roosevelt caused problems. In 1940 he was ousted as CIO President and in response withdrew the UMWA from the CIO, during the war he repeatedly ordered large miner strikes that shut down coal production and threatened the war effort. Roosevelt issued Executive Order 9340 that empowered the Department of the Interior to take possession of coal mines as appropriate, and operate them on behalf of the government. Miners previously employed by the companies operating those mines would be paid by the government, with many of the mine operators acting as agents for the government. Roosevelt also indicated in a letter he released with the executive order that he would make sure strict price controls were enforce in coal mining regions, as the most recent strike had been in part over wages not being sufficient to cover significant cost of living increases in coal mining areas.

During WWII the government through various boards was able to control the use of key commodities. I don’t know that even in WW2 Ford or Chrysler were told or ordered “to produce not a single more passenger car or else” but since the OPM and later WPA basically had control of all the raw materials they’d need for their business and had the authority to direct how those materials be used it basically meant there was no practical way to do anything other than cancel all passenger car production and start taking defense orders (no passenger cars were produced until after the war starting in February 1942.) Even without that, a lot of laws and rationing rules would have significantly limited the purchase of passenger cars in the consumer market even if the automakers had continued limited production. Plus the U.S. auto industry was a $4bn/year industry (but struggling due to the depression) prior to the war and received tens of billions in contracts with the military so they were more than happy to get the government business. It represented a dramatic increase in production and revenue for them.

There was tire and gasoline rationing that dramatically cut down on the amount of miles traveled by car and would have also meant fewer new car purchases (if there had been new cars to purchase.) There were also laws mandating a 35 mph national speed limit for gas conservation purposes and orders banning sightseeing driving. There was a stockpile of about half a million cars produced in the final few months that was intended to be used to provide vehicles for “essential drivers” as needed throughout the war period.

Generally speaking during WW2 so much military research was being done with significant Federal spending intermeshed it is unlikely very many new technologies would exist where the government did not have some level of claim on the technology as well. Additionally, the technique for managing the war economy always preferred private industry to do the work of production when possible. They would not have wanted to build government run factories and manufacture stuff unless something forced it (like they were forced to seize some coal mines–but even then they mostly let the previous operators operate them as agents for the government.)

When there is a governmental “taking” they have to compensate you. Actually during the period when they operated the coal mines one of the operators sued for compensation and won. So the government was allowed to forcefully seize/run them but not without compensating their owners.

Generally the government can draft you to do whatever it wants, it doesn’t have to be to fight. In the 1800s it was common for local governments to draft men for a few weeks out of the year and make them do local road repairs and such. I don’t have a cite handy at the moment but this was challenged at one point and made it to the SCOTUS where they affirmed it was a valid government power and such service was just a part of citizenship. But during WW2 I don’t think most of the scientists had to be forced, they wanted to do research anyway so why not take the government job with basically unlimited funding and resources at an important time in history.

One of the tricks was making sure that companies didn’t get contracts to produce armaments and things when they were better off producing whatever it was that they already did in peacetime.

Case in point- Union Switch & Signal was a company that made railroad switch and signal equipment in Pennsylvania. They did one contract to make M1911A1 automatic pistols, but were ordered to stop that and make their railroad equipment- apparently it was a better use of skill and resources to have them continue making the railroad equipment than pistols. I’m sure this kind of thing went on all over the place early in the war, but mostly got straightened out by 1945.