罷工、鎖廠、糾察以及杯葛是美國私部門中最主要之勞資爭議行為，勞資雙方透過上述行為給予對方經濟上之壓力，藉此迫使對方在相關爭議上妥協。在美國，第一個規範勞資爭議行為的重要聯邦法律是「一九三五年國家勞工關係法」，該法提供一個聯邦層級的基本法律架構來規範私部門的勞工關係。為落實國家勞工關係法第七條之規定，國家勞工關係法禁止雇主妨礙、壓迫或限制受僱人行使該法第七條權利之行為。國家勞工關係法不僅限制禁止雇主的特定行為，對工會的行為亦有所限制，例如該法對於工會進行「間接杯葛」即有實質的限制規定。 一九四七年，美國國會制定了「勞資關係法」，該法修正了「一九三五年國家勞工關係法」，擴大了國家勞工關係法的適用範圍。勞資關係法中所做的修正限制了工會的力量，並調整聯邦政府的角色，使其立場不再明顯地傾向有組織的勞動者，而能較為中立地處理勞資關係問題。 其他相關的聯邦法律還有「一九三三年諾利司-拉瓜迪亞法」，該法實質地限制聯邦法院介入勞資爭議之權限；以及「一九五九年勞資關係與揭露法」，該法修正了國家勞工關係法有關「間接杯葛」之規定，並禁止工會使用「熱貨條款」。 美國除了有成文法規範勞資爭議行為的正當性之外，還有為數龐大的普通法（案例法）。限於篇幅，本文僅針對相關聯邦勞工立法以及聯邦法院判決做探討。本文先就美國的勞資爭議行為做分類，從相關聯邦勞工立法以及個案論述勞資爭議行為的正當性，之後再提出美國相關法規範值得我國參考之處。

Strikes, picketing, boycotts and lockouts are the major weapons of labor-management confrontation in the private sector in the US. Both unions and employers use the weapons to place economic pressure on each other in order to prevail in the bargaining process. The first major federal statute affecting labor-management confrontation is the National Labor Relations Act of 1935. It provides an entire framework for governance of labor-management relations and protection of employee rights. The Act prohibits an employer from interfering with, restraining or coercing employees in the exercise of their Section 7 rights. The National Labor Relations Act imposes limits and duties on unions as well. For example, it imposes substantial limits on secondary boycotts by unions. The Labor Management Relations Act was enacted in 1947, which amended and expanded the National Labor Relations Act. The changes made by the Labor Management Relations Act limit the power of trade unions and move the federal government from the position of obvious advocate of organized labor to a more neutral position. The other related federal statutes include Norris-LaGuardia Act of 1932 and Labor Management Relations And Disclosure Act of 1959. The former substantailly limits the jurisdiction of the federal courts in matters arising out of labor disputes; the latter amends the law regulating “secondary boycotts” and prohibits unions from using “hot cargo” clauses. The labor-management confrontation law in the US includes statutes and common law (case law). Only related federal statutes and federal court decisions are discussed in this paper. At first, this paper classifies labor-management confrontation activities into strikes, picketing, boycotts and lockouts. It then discusses the legitimacy of these activities separately. At last, this paper will proposes some ideas to refer the relevant US law to the related problems in Taiwan.