Mr Patten said at a Tory dinner in London: "He has made an excellent start and deserves the loyal and enduring support so fatally denied his predecessor."
Mr Patten - regarded by some Conservative moderates as the best leader the party does not have - praised Mr Hague for holding the centre-right position of the party, for showing patience, and for taking a line on Europe that would avoid the risks of outright confrontation and division within Tory ranks.
The blessing could well be pivotal because of the respect Mr Patten attracts from the Tory moderates, and because it recognises the efforts Mr Hague has made to accommodate all elements of the party - while helping to nail down that position. In his speech to the outgoing Conservative Central Council at Harrogate on Saturday, Mr Hague repeatedly referred to the party's One Nation tradition; something Margaret Thatcher rejected as "wet".
Last night, Mr Patten said: "William Hague has been wise not to fall into the temptation which has claimed so many of the American Right when faced by a government in Washington doing some of what they believe in. Instead of standing where they are, welcoming whenever appropriate, fiscal prudence and market-oriented policies, and fleshing out a principled and coherent approach based on these virtues, many Republicans have veered off towards a right-wing agenda of bits and pieces - anti-abortion here, capital punishment there, with a few zany tax ideas thrown in.
"This is, I suppose, the American variant of the belief in 'clear blue water', the notion that if your opponents do some things you believe in that are popular, you should advocate more extreme things that are not popular. Mr Hague has sensibly avoided this.
"He has led the party from a position in its traditional centre with skill and determination. He possesses formidable parliamentary skill and an engaging unflappability" - both qualities for which Harold Macmillan, another moderate Tory leader, was noted.