爱因斯坦最早从事政治活动是在第一次世界大战，当时他在柏林当教授。由于目睹草菅人命而不胜厌恶，他卷入了反战示威。他拥护国内反抗以 及公开鼓励人民拒绝征兵，因而不讨他的同事们喜欢。后来，在战时他又致力于调解和改善国际关系。这也不得人心，而且他的政治态度很快使他难以访问美国，甚 至连讲学都有困难。
爱因斯坦第二个伟大的事业是犹太复国主义。虽然他在血统上是犹太人，但他拒绝《圣经》上关于上帝的说法。然而，第一次世界大战之前和期 间，他越发看清反犹主义，这导致他逐渐和犹太团体相认同，而后成为一个直言不讳的犹太复国主义的拥护者。再度不受欢迎也未能阻止他发表自己的主张。他的理 论一发表就受到攻击，甚至成立了一个反爱因斯坦的组织。有一个人被定罪为教唆他人去谋杀爱因斯坦（只罚了6美金）。但爱因斯坦是冷静的：当一本书以题为 《100个反爱因斯坦的作家》出版时，他反驳道：“如果真是我错了的话，那么一个人反对我就足够了！“
1933年，希特勒上台了，爱因斯坦正在美国，他宣布不再回德国。后来纳粹义勇军抄查了他的房子，并没收了他的银行账号。一家柏林报纸 的头条写道：“来自爱因斯坦的好消息——他不回来了。“面对着纳粹的威胁，爱因斯坦放弃了和平主义，终于忧虑到德国科学家会制造核弹，因而建议美国应该发 展自己的核弹。但是，即使在第一枚原子弹爆炸之前，他就曾经公开警告过核战争的危险，并提议对核武器进行国际控制。
贯穿爱因斯坦一生，他致力于和平的努力可能成效甚微——肯定只说服了很少的朋友。然而，他对犹太复国主义事业的口头支持在1952年被 及时承认，其时他被推荐为以色列的总统。但他谢绝了。他说他认为自己在政治上太天真。可是，也许其真正的原因却并非如此，再次引用他自己的话：“方程对我 而言更重要些，因为政治是为当前，而一个方程却是一种永恒的东西。“
Einstein’s connection with the politics of the nuclear bomb is well known: he signed the famous letter to President Franklin Roosevelt that persuaded the United States to take the idea seriously, and he engaged in postwar efforts to prevent nuclear war. But these were not just the isolated actions of a scientist dragged into the world of politics. Einstein’s life was, in fact, to use his own words, “divided between politics and equations.“ Einstein’s earliest political activity came during the First World War, when he was a professor in Berlin.
Sickened by what he saw as the waste of human lives, he became involved in antiwar demonstrations. His
advocacy of civil disobedience and public encouragement of people to refuse conscription did little to endear him to his colleagues. Then, following the war, he directed his efforts toward reconciliation and improving international relations. This too did not make him popular, and soon his politics were making it difficult for him to visit the United States, even to give lectures.
Einstein’s second great cause was Zionism. Although he was Jewish by descent, Einstein rejected the biblical idea of God. However, a growing awareness of anti-Semitism, both before and during the First World War, led him gradually to identify with the Jewish community, and later to become an outspoken supporter of Zionism.
Once more unpopularity did not stop him from speaking his mind. His theories came under attack; an anti-Einstein organization was even set up. One man was convicted of inciting others to murder Einstein (and fined a mere six dollars). But Einstein was phlegmatic. When a book was published entitled 100 Authors Against Einstein, he retorted, “If I were wrong, then one would have been enough!“ In 1933, Hitler came to power. Einstein was in America, and declared he would not return to Germany. Then, while Nazi militia raided his house and confiscated his bank account, a Berlin newspaper displayed the headline “Good News from Einstein – He’s Not Coming Back.“ In the face of the Nazi threat, Einstein renounced pacifism, and eventually, fearing that German scientists would build a nuclear bomb, proposed that the United States should develop its own. But even before the first atomic bomb had been detonated, he was publicly warning of the dangers of nuclear war and proposing international control of nuclear weaponry.
Throughout his life, Einstein’s efforts toward peace probably achieved little that would last – and certainly won him few friends. His vocal support of the Zionist cause, however, was duly recognized in 1952, when he was offered the presidency of Israel. He declined, saying he thought he was too naive in politics. But perhaps his real reason was different: to quote him again, “Equations are more important to me, because politics is for the present, but an equation is something for eternity.“