An Anglo-American war during the 1860s

How would an Anglo-American war in the 1860s differ from the War of 1812?

The much larger Royal Navy could blockade the whole United States, crushing trade and aggravating existing political divisions before American continental infrastructure matured.

The United States had not yet completed the rail and industrial integration that later made it a mature continental power. Britain could deploy far more ships and apply the same economic pressure that helped the Union defeat the Confederacy, but against the entire country. Because war support would not be universal and slavery already divided American politics, the Royal Navy could exploit both economic disruption and internal conflict.