Over the course of the past year, whenever people asked who would be the next president, I often said it was hard to answer that question because the election would be determined by headlines we haven’t yet seen. We know, for example, that the headlines from the Paris and San Bernardino attacks significantly impacted the Republican presidential primary.

The shocking death of Justice Antonin Scalia will change the presidential race yet again. It sets off what promises to be a brutal confrontation between Barack Obama and Senate Republicans.

Grassroots conservatives have zero tolerance for another cave in to this president. In fact, if Obama succeeds in appointing Scalia’s successor, it would be a double win for him. He would swing the court dramatically to the left and in the process ignite a civil war that could destroy the Republican Party.

Whether they want to or not, Republican senators must fight this fight. If Senate Republicans allow Scalia’s seat to be filled by Obama, they may as well cancel the election. Such a move would so demoralize the party’s conservative base that the GOP would likely lose anyway. And even if it did win, the odds are overwhelming that the Obama court would negate everything that Republican president attempted to do.

The Left’s Spin

You will hear all kinds of remarks about unacceptable obstructionism if the Senate majority refuses to confirm a justice this year. We will regularly debunk the arguments being made by the left in the months ahead. But I want to address a few today.

• The Kennedy “Precedent” — Many left-wing commentators are citing the confirmation of Justice Anthony Kennedy in February 1988 as the precedent for what should happen now. But there are several important distinctions to consider.

First, Kennedy was nominated in 1987 after Senate liberals had rejected Robert Bork, an intellectual giant. They not only defeated Bork, they eviscerated him and turned Supreme Court confirmations into a blood sport. They gave us a new term — to “Bork someone.” The effort was led by Ted Kennedy and Joe Biden. Nothing was off limits in their efforts to destroy Bork.

A second choice to replace Bork, Douglas Ginsburg, withdrew after it was reported that he had smoked marijuana many years earlier. Kennedy was Reagan’s third nominee. After stopping two nominees, Senate liberals thought Kennedy was someone they could take a chance on. As it turned out, they were right. Kennedy has voted repeatedly with the left on values issues.

What about their own precedent? In July of 2007 — well more than a year before George W. Bush’s term ended — Senator Charles Schumer (D-NY) vowed to block any Bush nominees to the Supreme Court, declaring, “We should reverse the presumption of confirmation.”

• The Constitution — There have been numerous suggestions in the past few days that the Constitution requires the president to nominate justices and the Senate is required to fill those vacancies. But during George W. Bush’s first term, liberals waged a relentless war against his judicial nominees.

In the summer of 2001, Senator Schumer chaired a Senate hearing on the judicial confirmation process specifically to highlight the Senate’s role in vetting the ideology of judges. In other words, Schumer was laying the groundwork for rejecting judges based on their judicial philosophy.

It didn’t take long for Senate liberals to implement Schumer’s strategy. In 2003, he unapologetically declared, “Yes, we are blocking judges by filibuster. That is part of the hallowed process around here.” Even well-qualified minority candidates like Miguel Estrada and Janice Rogers Brown were blocked.

Lastly, I find it truly ironic that Senate liberals are making this “good government” argument. Last fall, they rammed through a deal with Iran in which the constitutional responsibility of the Senate to consider treaties was completely ignored.

The White House used every ounce of power it had to make sure senators never got the opportunity to vote on the deal itself. I don’t recall any media commentary questioning why the White House and its Senate allies were trying to guarantee that the Senate would never vote on the Iran nuclear treaty.

• Obama Won — Here’s an argument you might even hear some Republicans make: Elections have consequences, and Obama won the White House so the public wants Obama to appoint judges. Well, after Obama was re-elected, Republicans won the Senate in 2014 and it is the Senate that ultimately confirms judicial appointments.

• Obama’s Stealth Nominee — There is a lot of speculation about who might be on Obama’s short list to nominate to the Supreme Court. Some think he might pick a candidate who is perceived to be a moderate and who was previously approved by an overwhelming vote for a lower court position.

But the process of deciding who is confirmed to the Supreme Court is a much different process. A lopsided vote in favor of a lower court appointment DOES NOT MEAN that that person should be put on the highest court in the land.

Don’t fall for the ruse that Obama will appoint a moderate. Can anyone name the last truly moderate justice appointed by a Democrat president?

This next appointment is filling the void left by a conservative giant. We are now facing a court with four lock-step liberals, two strong conservatives in Thomas and Alito, Chief Justice Roberts, who is generally good but has disappointed conservatives on occasion, and Anthony Kennedy, who is completely unreliable.

Another Kennedy on the court would give us four liberals, two left-leaning moderates and at best three conservatives. There would be a lot of 6-to-3 decisions against our values. In short, it would be a catastrophe.

But I can just imagine the scenario now: Obama invites a handful of Senate Republicans to the White House and makes his pitch to help unite a divided country. Polling shows that the public is against “obstructionism.” Weak-kneed senators conclude that they are standing tough and that this “moderate” is the best we could expect to get. But they would be buying into a disaster, substituting an Obama vote for a man who was always with us.