Grasp The Nettle Meaning

Example : 1886, "London's Recent Rioting," New York Times, 22 Feb., p. 5 (retrieved 18 Aug. 2010):  Hence it was that a few dozen policemen, resolutely grasping the nettle, had no difficulty in handling it.1951, "From Today's Times," Ottawa Citizen (Canada), 30 April, p. 2 (retrieved 18 Aug. 2010):  President Truman, when at last he grasped the nettle and dismissed MacArthur, knew well enough the outcry that would follow.2007, "Brown's Britain: taking the nuclear option," telegraph.co.uk, 24 May (retrieved 18 Aug. 2010):  That Tony Blair should wait until the dying days of his premiership before grasping the nettle of nuclear expansion has proved dangerously neglectful.