There is controversy over President Barack Obama’s nomination of Judge Merrick Garland to the Supreme Court of the United States on March 17, 2016.

Lines have been drawn. President Obama insists the Senate hold hearings and confirm his nominee. The Senate, led by majority leader Mitch McConnell, R-Kentucky, has refused to hold hearings. This is serious business because both the president and every Senator have taken an oath to abide by the Constitution and ought to be led by its dictates.

Those opposed to holding hearings have been emboldened by the publication of a list of possible nominees by the presumptive Republican nominee for president, Donald Trump. That list includes many highly respected conservatives, including Justice Thomas Rex Lee of Utah.

There are three strands of conservatism raised in the confirmation controversy: 1. the judiciary should defer to members of Congress when they are exercising their power, to avoid judicial legislation; 2. a rights-based, or libertarian approach, that calls for judicial intervention when rights are infringed by the majoritarian branches of government; and 3. an approach that focuses on the original meaning of the words of the Constitution.

In refusing to hold hearings, the Republican leadership looks at only one strand — it defers to its own power, invoking the so-called “Biden Rule.” In 1992, then-Senator Joe Biden was serving as chairman of the Judiciary Committee. In that capacity, he stated his “pragmatic conclusion that once the political season is underway, and it is, action on a Supreme Court nomination must be put off until after the election campaign is over.”

Recently, one of the most respected voices in the Senate, Sen. Orrin Hatch, R-Utah, argued against holding hearings on the ground of precedent: “The Senate has never confirmed a nominee to a Supreme Court vacancy that opened up this late in a term-limited president’s time in office.”

Others argue that multiple justices have been nominated and confirmed in presidential election years during the past century. Both sides argue like lawyers, carefully wording their points to support their position. This is what we call "law office history."

The conclusion: precedent is unclear. Furthermore, it is not a question of what has been done and when it was done. It is what the Constitution mandates. Two strands of conservative constitutional thought speak to that issue.

The second strand — the rights-based view — may be implicated. It protects the right of the nominee, Judge Garland, to due process and a hearing. Judge Garland has been nominated and should receive a hearing unless the president withdraws his nomination.

The third strand of constitutional conservatism requires that senators examine the meaning of the appointments clause, Article II, Section 2, Clause 2. The Federalist Papers, which were published to secure ratification of the Constitution, are considered a primary source in determining constitutional meaning.

Most Senate Republicans begin and end by invoking their legislative power, undisturbed by intervention from the judicial or executive branches. They are anxious to deal the president a blow by rejecting his nominee outright. In doing so, they fail to recognize they are setting a precedent based on a liberal position, the Biden rule.

The two other strands of conservatism demand more than this. The rights-based view may be implicated, not to protect the president’s right to appoint, but to secure the right of Judge Garland to due process, to a fair hearing. Courts generally reject this right as little more than a bootstrap – using a nominee’s purported individual right as a means of effectively affirming presidential power. Senators, nevertheless, should be sensitive to such due process rights.

The third strand of conservatism requires senators examine the meaning of the appointments clause, Article II, Section 2, Clause 2. The Federalist Papers, which were published to help secure ratification of the Constitution, are generally considered to be a primary source in determining constitutional meaning.

In Federalist No. 76, Alexander Hamilton discusses the meaning of the appointments clause. Hamilton declared, “(T)he power of appointment, in ordinary cases, ought to be modified in one of three ways. It ought either to be vested in a single man, or in a SELECT assembly of a moderate number; or in a single man, with the concurrence of such an assembly.” He explains further that the framers opted for the better of the three options: the appointment of Supreme Court justices by a single person (the president) “with the concurrence” (advice and consent) of a moderately sized legislative body (the Senate).

Under this strand of conservatism, the president and the Senate are constitutionally required to engage in a concurrence process in appointing justices to the Supreme Court. The Oxford dictionary defines “concurrence” in two ways: 1. “The fact of two or more events or circumstances happening or existing at the same time”; and 2. “Agreement or consistency.”

In concurring, the president nominates and the Senate holds hearings to determine whether they consent to a given nominee. If, after full vetting of a nominee through public hearings, the Senate rejects the nominee, the president nominates another candidate. This process balances the powers of the Senate and the presidency and has served our nation well.

By refusing to concur and hold hearings, the Republicans are setting a troubling precedent that may violate two strands of constitutional conservatism. Senators who are true to all three strands should hold hearings. If necessary, they may reject a given nominee, offering reasons for why the nominee is unacceptable. But, they are mandated to hold hearings.

The refusal of Senators to hold hearings may be politically prudent, but it is contrary to conservative principles and may violate their oath to abide by the Constitution. May the Republicans in the Senate hold hearings and thereby exercise constitutional courage in furthering the rule of law rather than indulging in yet another act of political expediency.

Rodney K. Smith is a professor of practice at the Sandra Day O’Connor College of Law, Arizona State University.