When he was nominated for a federal judgeship in 2006, Neil Gorsuch was confirmed by voice vote in the Senate and there was not a single objection to an obviously qualified nominee. Though no one is expecting as smooth a ride for Gorsuch as President Trump’s nominee to the Supreme Court, his qualifications are just as undeniable. The position of Senate liberals seems to be, “Announce your opposition, and find reasons later,” but they will quickly learn it’s a very tough case to make.

Like the justice he would succeed, the late Antonin Scalia, Gorsuch is highly regarded in legal circles for qualities having little to do with politics or ideology. Democrats and Republicans alike know him as a judge of extremely impressive ability, uncompromising in his sense of fairness and in his personal integrity.

In a 25-year legal career, Gorsuch has clerked for two Supreme Court justices (one appointed by John F. Kennedy, the other by Ronald Reagan), served in the Department of Justice, spent a decade in private practice, and has now served another decade on the U.S. Court of Appeals for the 10th Circuit. He has written more than 200 opinions for that court, marked by insight and clarity that have drawn comparisons to the style of Scalia.

As with Scalia, moreover, Gorsuch’s style is a reflection of a judicial philosophy that begins with deference to written law. This puts him at odds with progressives who have spent decades urging courts to invent new rights, or to disregard old ones, according to the latest ideological fashion.

Exactly as the president promised, this is a judge who understands the proper limits of his office, never mistaking personal preference for constitutional mandates. Judges, as Gorsuch has written, “should be in the business of declaring what the law is using the traditional tools of interpretation, rather than pronouncing the law as they might wish it to be in light of their own political views.”

For most of American history, this understanding of the difference between judging and legislating was practically the definition of faithful jurisprudence. Yet, nowadays, liberals regard it as too narrow and “out of the mainstream.”

The progressive agenda depends on judges who are activist in reaching beyond the rule of law’s limits in constitutional cases, but who are completely passive in allowing agencies to go beyond statutory bounds in regulatory cases — and Gorsuch is clearly not that kind of judge. The president has nominated, instead, a person of both modesty and character — not given to judicial overreach, but firm and decisive in upholding the rights guaranteed in our Constitution and laws.

Religious liberty, for instance, was on the line in several notable cases that came before Gorsuch’s 10th Circuit court during the Obama years. Federal authorities, in enforcing the mandates of the Affordable Care Act, had been hounding an order of Catholic nuns, the Little Sisters of the Poor, for resisting intrusive regulations on grounds of conscience. After a panel of his own court ruled against the Little Sisters, Gorsuch urged his colleagues to reconsider. When the case went to the Supreme Court, the justices essentially agreed with his argument that the government had shown too little regard for a legitimate claim of religious freedom.

It was a similar story in the 2013 case Hobby Lobby Stores v. Sebelius. The government argued that Obamacare regulations took precedence over the sincere religious convictions of the owners of the Hobby Lobby chain. Concurring with the majority in favor of Hobby Lobby, Gorsuch defended the right of business owners not to be compelled to adopt practices they know to be contrary to their religious faith. His reasoning prevailed again at the Supreme Court, in what is now a landmark case for religious freedom in America.

Hobby Lobby was also closely decided, in a 5-4 split with Scalia, of course, in the majority. And though the progressive left, until late on the evening of last Nov. 8, had every expectation of replacing Scalia with one of their own, it didn’t work out according to plan. Their upset defeat on Election Day has left them so resentful and desperate that they pledged to block the nominee by filibuster even before knowing the name. It’s a cheap and transparently unfair tactic, and it can succeed only if enough Senate Democrats cave to partisan pressure and play along.

The surest proof that someone is “outside the mainstream” is blind hostility to the nomination of this highly respected jurist.

By any reasonable measure, Neil Gorsuch is a man of superb qualifications, with well-known convictions and a demonstrated commitment to the Constitution. On the bench, he has proven his good faith and independence, and soon it will be time for Senate Democrats to prove theirs.

Rick Santorum attended Butler schools and is a former U.S. senator from Pennsylvania. He wrote this for the Philadelphia Inquirer.