The Constitution certainly gives President Obama the right to appoint a candidate to replace Justice Antonin Scalia on the Supreme Court, but the U.S. Senate also has the constitutional right to approve or reject that choice. Many Republicans believe it is unseemly, and violates past tradition, to appoint new Supreme Court justices in the last year of a president’s lame-duck term in office, because the soon-to-be successor president should have that prerogative.
To which Democrats have responded that, speaking of tradition, the Senate should defer to the president in his choice of government officials, especially since the Constitution gives him the power to appoint “judges of the Supreme Court and all other Officers of the United States,” (again, provided two-thirds of the Senate approves of that choice).
“Officers of the United States,” includes the heads of the Executive Branch departments — the State Department, Defense Department, Treasury, Education, and so on — and generally the Senate should defer to the president in picking those who will work closely with him in his Cabinet.
Supreme Court justices, however, are different. They serve in the Judicial Branch of the government, which according to the “separation of powers” principle embedded into the Constitution, is supposed to be separate and entirely independent of both the Executive and Legislative branches. Therefore senators, as members of the Legislative Branch, have both a right and duty to ensure that a president’s nominee to the Supreme Court is not overly shaped by the president’s philosophy or ideology, which, liberal or conservative, is itself shaped by political considerations, while judges are charged with apolitically interpreting the constitutionality of the laws. If the Senate defers too much to the Executive Branch in terms of the judges it appoints to the Judicial Branch, then that Judicial Branch is likely to become an adjunct of the Executive Branch, and the “separation of powers” doctrine is violated.
Thus the Senate should judge how Supreme Court nominees will affect public policy based on their fidelity to the Constitution’s language and established law, all the more so since presidents and the policies they put in place come and go, while federal judges serve for life, meaning they are affecting public policy long after the presidents who appointed them are gone.
On that note, President Obama once said his Supreme Court nominees should have “empathy,” meaning their feelings should shape their rulings as much as their understanding of the Constitution. He also once criticized a Supreme Court that was actually quite liberal (the Warren Court) because it “didn’t break free from the essential constraints that were placed [on it] by the Founding Fathers in the Constitution …”
In other words, he was upset that that Supreme Court abided by the Constitution.

