There are two meanings of "liberal". The original meaning was supportive of individual liberty, and still tends to be the dominant sense outside of America. In America, "liberal" has come most often to refer to a sort of social democratism (mild socialism).

Before and during the Kennedy Administration, John and Robert were pragmatic technocrats. John was in alliance with Joseph McCarthy even as McCarthy recklessly accused people of being Soviet agents and sympathizers, and Robert worked on McCarthy's staff. John was elected to the Presidency by playing upon American fears of the Soviet Union. John told the nation that the Republicans had allowed a "missile gap" to develop, and that more active government measures were needed so that the Soviets would not outperform America economically and scientifically.

One of the reforms of the Kennedy Administration was to change the structure of the income tax, reducing marginal rates to improve incentives. (This proved very effective.) The Kennedy Administration was slow to defend racial equality and presented budgets that spent twice as much on the military as on domestic programmes. Meanwhile, with Robert as Attorney General, it routinely violated the Bill of Rights to gather evidence.

After the assassination of President John F Kennedy, Robert began to move politically to the left. He advocated aggressive socialistic programmes to combat poverty, became more supportive of civil rights, and opposed the escalation of American involvement in the Viet-Nam War. Some saw this as opportunistic, others as part of a sincere evolution begun with his brother's death; many people didn't think of it at all, swept-up in the mythology being spun around John F. Kennedy.

One can only guess what Robert would have done had he been elected President.

Edward Moore Kennedy has been reluctant to confront some of the actions of John and Robert, but he has denounced illegal search-and-seizure by later administrations. He has positioned himself as not merely in favor of racial and sexual equality, but of "affirmative action" (discrimination to off-set the effects of past discrimination). He was at one time the foremost advocate of socializing health-care delivery in the United States. So, in some respects, he seems more concerned with liberty than were his brothers; and, in other respects, he has been more socialistic.

He has become somewhat more quiescent in later years, as he has been repeatedly embroiled in personal scandal, as America has moved generally away from liberalism (in both senses of the word), and as he has grown old.
It is of Irish and Gaelic origin, and its meaning is helmet head or ugly head; one who had an ugly head .