After graduation, Sawyer joined the law firm of
Drinker Biddle & Reath, where he remained for his entire career. Shortly after joining the firm, he was assigned to work as a temporary assistant district attorney in the
O'Malley Case, a prosecution of political corruption in the city (the
Philadelphia district attorney's office at that time was mostly staffed by part-time employees drawn from firms as needed). Working under lead prosecutor
Laurence Howard Eldredge and alongside assistant prosecutor
Lemuel Braddock Schofield, Sawyer assisted in the trial of Chief Magistrate
John J. O'Malley for 206 counts of
malfeasance in office. O'Malley was found not guilty in two trials in 1948 and 1949. Sawyer was called back into the Navy in 1950 during the
Korean War and later as a foreign service officer in Europe. He returned to Philadelphia in 1953. As a lawyer, Sawyer focused on civil litigation in corporate law, at which he excelled. He also spent much of his time in the field of civil liberties, for which he became more well-known but less well-compensated. In 1951, with
Sadie T.M. Alexander and others, he co-founded the Greater Philadelphia Branch of the ACLU. In 1953, he was one of several volunteer (
pro bono) defense attorneys in the case of
United States v. Kuzma, a prosecution of
Communist sympathizers under the
Smith Act, which barred anyone from advocating for the overthrow of the American government. The defendants were found guilty, but their convictions were reversed in 1957 after the
United States Supreme Court overturned the Smith Act in
Yates v. United States. Sawyer argued again in favor of someone accused of communist sympathies in
Deutch v. United States. Sawyer's client, Bernhard Deutch, was a graduate student at the University of Pennsylvania who was subpoenaed by the
House Un-American Activities Committee in 1954. Deutch answered most of the committee's questions about his own former membership in the
Communist Party as an undergraduate at
Cornell University, but declined to answer questions about other members of the party, asserting that his "moral scruples" prevented him from doing so. The House found Deutch in
contempt, and the charge was upheld in federal district court. The
D.C. Circuit Court of Appeals affirmed the conviction, which Sawyer appealed to the Supreme Court. To his surprise, they took the case and reversed the conviction on the grounds that the government failed to prove "the pertinence of the questions". Pollak credited Sawyer's advocacy at the district court level with helping to win the case: "it is clear that a masterly litigator planted in trial court the seeds of the fruit that was to ripen on appeal."
Lemon v. Kurtzman Sawyer further shaped the church-state landscape a few years later in the case of
Lemon v. Kurtzman. In 1968, Pennsylvania enacted the Nonpublic Elementary and Secondary Education Act, which allowed the state to reimburse non-public schools for education costs, provided that the costs were not incurred in teaching religion. Although the statute specifically barred state funds from paying for "any subject matter expressing religious teaching, or the morals or forms of worship of any sect", civil rights activist
Alton Lemon believed the law still allowed for the state to effectively fund religious schools, a violation of the Establishment Clause. Sawyer took the case and brought suit in district court. Again arguing before a three-judge panel, Sawyer was initially unsuccessful. Judge
Emanuel Mac Troutman, writing for the panel, explained that under the rules set forth in
Schempp, the Act had a secular purpose and did not fund religion. Sawyer appealed and the Supreme Court granted
certiorari in 1970. In an opinion handed down on June 28, 1971, the Court held for Sawyer's client and struck down the Pennsylvania law. Chief Justice
Warren E. Burger, writing for a seven-justice majority, held that "the cumulative impact of the entire relationship arising under the statutes in each State involves excessive entanglement between government and religion." The test handed down in
Lemon remains the core of the process for determining whether a state action violates the Establishment Clause. According to the ruling, a statute does not violate the Establishment Clause so long as it has a secular purpose, its principal effect does not advance or inhibit religion, and it does not foster an excessive government entanglement with religion. After
Lemon, Sawyer was regarded as among the premier appellate litigators. Justice
William J. Brennan Jr. said to Sawyer in 1988 that "few lawyers have equaled your advocacy." ==Local politics==