Murray Rothbard popularized the concept of the welfare-warfare state. He didn’t like either of them. He knew that if the state was doing anything there was plunder involved. Welfare was any handout from the government to anyone. One book that handled warfare and welfare systematically was Crisis and Leviathan by Robert Higgs.
Imperialism and social reform cover the same relationships. Many tried to reconcile government with liberty. They called themselves Progressives. They’ve loved warfare and its welfare opportunities. The Cold War was perfect for this agenda until the Soviet collapse took away the enemy. Stromberg mentions many historians and their books on this topic.