Final answer:
The opinion in Douglas v. California was influenced by two constitutional amendments/rights: the Fourteenth Amendment's guarantee of equal protection under the law, and the right to counsel as a part of due process.
Step-by-step explanation:
In the case of Douglas v. California, two different constitutional amendments/rights seemed to underlie the opinion. The first is the Fourteenth Amendment, which guarantees the right to equal protection under the law. This amendment was referenced in Justice Douglas' argument that the Bill of Rights should be fully applied to the states. The second is the right to counsel, which is protected by the Constitution as a part of due process. Justice Clark argued that this right should not be selectively applied, but rather available to all individuals in criminal cases.