Is war with China on the horizon?

[Minimalist]

That's not what this says:

https://en.wikipedia.org/wiki/Sino-Indian_War#Ceasefire

China had reached its claim lines so the PLA did not advance farther, and on 19 November, it declared a unilateral cease-fire. Zhou Enlai declared a unilateral ceasefire to start on midnight, 21 November. Zhou's ceasefire declaration stated,

Beginning from 21 November 1962, the Chinese frontier guards will cease fire along the entire Sino-Indian border. Beginning from 1 December 1962, the Chinese frontier guards will withdraw to positions 20 kilometres behind the line of actual control which existed between China and India on 7 November 1959. In the eastern sector, although the Chinese frontier guards have so far been fighting on Chinese territory north of the traditional customary line, they are prepared to withdraw from their present positions to the north of the illegal McMahon Line, and to withdraw twenty kilometres back from that line. In the middle and western sectors, the Chinese frontier guards will withdraw twenty kilometres from the line of actual control.

Since India had asked for - and been granted - American assurances of air support it seems likely that the Chinese were simply not willing to risk a confrontation with the US.  Maxwell Taylor and Robert MacNamara recommended the use of nuclear weapons if the US had to intervene later on in support of India.  So what is a footnote to history might well have become something far more significant.

And the British were always drawing lines on maps.  That's a major reason we are up to our assholes in shit in the Middle East.