Britain was very much trying to align with Japan at this point. They had a history of cooperating in Asia, had deliberately stayed aloof from the agreements in the aftermath of the Sino-Japanese War which forced Japan to give up territory, and was able to trust Japan to help out in the Boxer Rebellion. The British were also constantly fearing Russian expansion in Central Asia and the Far East, for fear of invasion of India. What Britain didn't want to do was get involved in a grand scale European war due to activities in Asia, hence the provisions of the Anglo-Japanese alliance making it a naval agreement to counter France and Russia in the Far East. When the 1905 war came round, both Britain and France were eager to distance themselves from their allies in their Entente negotiations.
Despite this, Britain also wanted to improve relations with the USA. It wanted to improve them in the early 20th century so as it could stop worrying about its Carribean posessions, and it wanted to improve them in the 1920s to stop a naval race, get war debts reduced and lead the world in disarmament. It would take a fabulously dim view of Japan invading the Western seaboard of the USA. There were admittedly some voices in the British government advocating renewing the Anglo-Japanese Alliance, but these would be overwhelmed if their increasingly unreliable and aggressive ally (the 21 Demands on China, for example) decided to leap into another war to "liberate" the USA. The British would at least maintain benevolent neutrality (benevolent to the USA that is) and build up their forces in Asia, watching Japan fail in their war. A Royal Naval task force would probably be unneccessary and expensive, especially without the base at Singapore, but would earn them some nice brownie points from the USA for war debt reduction purposes.
This post was completely pointless, but never mind.