There is no problem that is really difficult relative to raising the money to buy what has to be produced. The government will provide the demand with money that can come either through taxes, borrowing, or if necessary, various other inflationary means.
"Economic Elements of U.S. War Potential,"
Naval War College Review: Vol. 3
, Article 4.
Available at: https://digital-commons.usnwc.edu/nwc-review/vol3/iss5/4