Samuel Gompers, a poor immigrant who laid much of the foundation of the American labor movement, once observed that ''my legs are so short I can never run away from a fight.''
Neither has organized labor much since then. Though not advocating violence, unions have long been scrappy champions of the worker.
But today the tactics some unions use in wringing concessions from management and jawboning nonunionized workers to join the local brotherhoods are coming under closer scrutiny.
Foes of big labor, trying to capitalize on the more conservative mood of the country, are pushing to curb what they see as a long-standing labor problem: union violence. Congressional efforts now are under way to make serious clashes on picket lines and in other labor disputes a federal crime.
Some observers see that as overreaction, since there seem to be few reliable statistics on the seriousness of the problem.
Nevertheless, the controversy sets up something of a political problem for the Reagan administration. The President's traditional conservative backers are pushing him to get tough on unions at the very time when he is trying to repair his damaged relations with organized labor. The outcome of the dispute could serve as a litmus test of the power labor still wields in the corridors on Capitol Hill.
The controversy revolves around efforts to change the Hobbs Act, a measure passed in 1946 to outlaw violence and extortion in interstate commerce.
Senate conservatives are pushing a measure that effectively would overturn a Supreme Court decision exempting unions from the federal antiextortion law in certain cases. The court, in 1973, ruled that Congress didn't intend for federal marshals to police union violence when the workers' actions were designed to achieve legitimate collective-bargaining objectives.
The Senate bill also would create new federal crimes for aggravated assault and property destruction in labor disputes. If passed - and congressional staffers aren't sure at this point of its chances - union officials contend it would thwart legitimate labor activity. They worry that a minor scuffle on a picket line could draw a stiff federal sentence.
As it is now, state and local authorities police most labor disputes. Union officials think they are up to handling the task. ''We don't condone that (violent) activity,'' says Howard Marlowe, associate director of legislation for the AFL-CIO. ''(But) what this move would do is elevate harsh words and a fist fight into 20 years in prison and a $250,000 fine.''
Yet backers of the measure - spearheaded by the National Right to Work Committee, a group opposed to compulsory unionism - argue that state and local police too often shy away from arresting local labor leaders.
The squabble has come at an awkward time for the Reagan administration, which is trying, at least on the surface, to smooth relations with big labor. The administration has delivered a split decision on the union violence bill. At recent hearings before a Senate Judiciary subcommittee, a Justice Department official backed plugging the loophole created by the Supreme Court, provided the federal law didn't apply to minor picket-line scuffles and that it covered management-spawned violence as well as union-initiated strife.
But the administration opposed widening federal law to include assault and property damage.
At the heart of the debate is just how widespread labor violence really is. Neither the FBI nor the Labor Department tracks the number of violent labor incidents that occur each year - a sign, some contend, that it is more an occassional occurrence than a widespread problem. The only agency that seems to keep tabs at all - the Treasury Department's Bureau of Alcohol, Tobacco, and Firearms - lists the amount of property damage that occurs as a result of labor-related bombing incidents.
This figure includes management - as well as union - spawned acts. The tally for 1980: $1.2 million in property damage, up from $646,000 the year before.
Trumpeting the problem of union violence the loudest is the National Right to Work group, which today claims 1.5 million members. The organization, through media accounts, claims to have recorded more than 20,000 incidences of union violence in the past six years.
As part of its lobbying pitch, it has produced a 30-minute ''documentary'' on union strong-arm tactics, ''The Scepter of Violence.'' The AFL-CIO has produced its own six-minute reel rebutting the charges. Both sides now are trying to get their films on television.
The Right to Work group sees victory with its union violence bill. ''This is the first time in almost 25 years that a bill restricting compulsory unionism in any way has had a hearing in Congress,'' claims Reed Larson, president of the Right to Work committee.
Some outside analysts, however, question the need for such measures. If anything, they point out, labor clashes seem to be on the downswing. Labor negotiations are no longer the stormy sessions they once were. The disputes have become more legal, routine.
What's more, labor unions today face dwindling memberships, slimmer paychecks , and less political clout. They are in no position, analysts argue, to go on the offensive. ''There aren't very many unions that would be able to take their members out today - because they wouldn't be able to get much,'' says Ronald Seeber, a collective bargaining specialist at Cornell University.