In 1824, in retirement 37 years after serving as the Constitutional Convention’s prime mover, James Madison, 73, noted that the 1787 “language of our Constitution is already undergoing interpretations unknown to its founders.” He knew that the purport of the text would evolve “with the changeable meaning of the words composing it.”

Now, 147 years since ratification of the 14th Amendment, its guarantees of “equal protection of the laws” and “due process of law” mean that states, which hitherto controlled marriage law, must recognize same-sex marriages. Anthony Kennedy’s opinion for the court said: “The generations that wrote and ratified the Bill of Rights and the Fourteenth Amendment did not presume to know the extent of freedom in all of its dimensions, and so they entrusted to future generations a charter protecting the right of all persons to enjoy liberty as we learn its meaning.” (Emphasis added.)

Many conservatives detect in those five words a dismaying intimation of a “living Constitution” too malleable to limit government because it conforms to whatever shape serves transitory political and cultural impulses. Conservative wariness is wise. So too, however, is recognition that Chief Justice Warren was not wrong when, in a 1958 case concerning the Eighth Amendment’s proscriptions of “cruel and unusual punishments,” he said: “The amendment must draw its meaning from the evolving standards of decency that mark the progress of a maturing society.”

Such evolution is real and relevant. No one today thinks that branding and ear cropping, which were punishments practiced when the Eighth Amendment was ratified, are today compatible with this amendment.

During April’s oral arguments, Chief Justice John Roberts said that people seeking same-sex marriage are “not seeking to join the institution” but are “seeking to change what the institution is.” But this institution has been changed by American attitudes and behavior. Marriage in America will be, over time, what Americans say it is, and last week’s decision came with almost three in four Americans already living in states where same-sex marriage is legal.

The decision came after Roberts showed conservatives the reality of judicial deference that they have often, and often thoughtlessly, advocated. Deferring to “what Congress meant to do,” Roberts rescued the Affordable Care Act from what he called Congress’ “inartful” means of doing it. The marriage and ACA decisions should cause the 2016 contest for the Republican presidential nomination to force candidates to clarify their thinking about the judiciary’s appropriate role in our constitutional system.

Although there is no interesting debate about this (or anything else) among Democrats, among Republicans there is a lively debate about whether the judiciary’s primary duty is to facilitate majorities’ powers or to protect individuals’ rights. Which makes this a perilous moment for Republican candidates, who might compete to propose constitutional amendments that dramatize their dismay about the same-sex marriage decision.

Scott Walker’s minimalist amendment, concerning process rather than policy, would restore the traditional state control over marriage law.

Others endorse an amendment defining marriage as between a man and a woman. Ted Cruz also endorses “judicial retention elections”:

“Every justice, beginning with the second national election after his or her appointment, will answer to the American people and the states in a retention election every eight years. Those justices deemed unfit for retention by both a majority of the American people as a whole and by majorities of the electorates in at least half of the 50 states will be removed from office and disqualified from future service on the court.”

Cruz’s idea is congruent with the 1912 proposal of another rambunctious Ted, former president Theodore Roosevelt. Running as a full-throated Progressive (against another progressive, Democrat Woodrow Wilson, and the conservative Republican president and future chief justice William Howard Taft), TR advocated not just the recall of judges but also “the review by the people” of “certain” judicial decisions. TR embraced the core progressive belief that the ideal of limited government, and hence the reality of the separation of powers, are anachronisms.

It is, therefore, especially disheartening that Cruz, who clerked for Chief Justice William Rehnquist and who is better equipped by education and experience to think clearly about courts, proposes curing what he considers this court’s political behavior by turning the court into a third political branch. Imagine campaigns conducted by justices. What would remain of the court’s prestige and hence its power to stand athwart rampant executives and overbearing congressional majorities? Sixteen months before the election, some candidates are becoming too unhinged to be plausible as conservative presidents.

Disclosure: This columnist’s wife, Mari Will, works for Scott Walker.

© 2015, Washington Post Writers Group