How Coast Guard cutters reinforce the US Navy

Would the United States arm Coast Guard cutters more heavily if conflict with China became likely?

Probably; the cutters can accept additional weapons and would take coastal-defense and convoy duties that free Navy ships for overseas combat.

Heavier cutter armament is considered likely if war with China appears imminent, since cutters have provision for weapons they do not routinely carry. Any expansion would still depend on sustained funding for the relevant US departments. The Coast Guard's wartime coastal patrol and convoy duties can release Navy ships for overseas operations, as happened during the Second World War. Its domestic law-enforcement responsibilities give it a different remit from a rescue service such as the RNLI. Cutters also serve overseas, and former US Coast Guard vessels can receive heavier weapons after transfer to other countries.