Some of President Obama's most ardent supporters have accused Republicans of "politicizing" the Ebola crisis. It's not a terribly serious accusation; a public health emergency requires the response of many government agencies, so how could politics not be involved? There's nothing wrong with that.

One specific charge, though, deserves an answer. The Ebola scare has made many Americans aware that there is no U.S. surgeon general. (The post is filled by an acting official who is not in line for the job.)

There is, however, an Obama nominee for surgeon general, Dr. Vivek Murthy, who has not been confirmed by the Senate after more than a year of waiting. Why hasn't Murthy won Senate approval in all that time?

To hear some of the president's advocates tell it, it's the Republicans' fault. "GOP blocks Surgeon General nominee," tweeted Eric Boehlert of the pro-Obama group Media Matters. "After blocking surgeon general nominee, Republican blames Obama for surgeon general vacancy," added another pro-Obama group, ThinkProgress.

Before getting into the details, here is the basic fact about charges that Republicans are blocking the surgeon general nominee: There are 55 Democrats in the Senate. Since Majority Leader Harry Reid changed the rules to kill filibusters for nominations, it would take just 51 votes to confirm Murthy. Democrats could do it all by themselves, even if every Republican opposed. But Democrats have not confirmed Murthy.

The reason has more to do with Murthy himself than anything else. As doctors go, he is a very political man, so it's no surprise his politics have created political problems.

In 2008 Murthy, a Yale-trained physician currently affiliated with Harvard, founded a group called Doctors for America. Actually, he first called the organization Doctors for Obama; after Obama's victory, Doctors for Obama became Doctors for America. The group devoted itself to lobbying for passage of Obamacare.

The organization's political focus continued after the Obamacare battle was won. In 2012, Murthy got a lot of attention when he expressed frustration with opponents of his preferred gun control policies. "Tired of politicians playing politics w/guns," he tweeted, "putting lives at risk b/c they're scared of NRA. Guns are a health care issue."

In January 2013, after the Sandy Hook shootings, Doctors for America sent a letter to Congress advocating an assault weapon ban, universal background checks, mandatory waiting periods, a gun buyback program, and other proposals favored by gun control groups.

If nothing else, the letter showed that Murthy's approach to his profession remained deeply political. In any event, Murthy's activism came back to haunt him in November of 2013, when the president nominated him to be surgeon general.

Republicans questioned Murthy's experience, which did not include public health administration. George W. Bush's surgeon general, Richard Carmona, said the 37 year-old Murthy is "very early in his career with great potential but no significant related leadership experience and no formal public health training or experience." (Lest the Bush association seem overly partisan, Carmona ran for Senate in 2012 as a Democrat.)

Beyond inexperience, what really troubled Republicans was Murthy's determined political advocacy, particularly on guns.

The National Rifle Association took a strong stand against Murthy, a position that caught the attention not only of Republicans but of red-state Democrats seeking re-election.

"Murthy's previous statements about gun control being a public health issue made him toxic to Democrats in cycle like [Mary] Landrieu, [Mark] Pryor, and [Mark] Begich," says one senior Republican aide.

In February, the Health, Education, Labor and Pensions Committee voted along party lines to send Murthy's nomination to the full Senate. It has sat there ever since.

It would take just 51 of the Senate's 55 Democrats to confirm Murthy. But that confirmation has not happened. "There is bipartisan opposition, so Sen. Reid hasn't even tried to bring him to a vote," says another senior Senate GOP aide.

By the way, Reid, who has never been shy about criticizing Republicans, is not among those publicly blaming the GOP for inaction on Murthy. A Reid spokesman did not respond to a request for comment.

Now the Murthy standoff has become entangled in the politics of Ebola. Given the confusion that has sometimes reigned at key health agencies like the Centers for Disease Control and Prevention, there's no reason to believe a confirmed surgeon general would have miraculously made the Obama administration's response more coherent and effective.

Nevertheless, some of the president's supporters have suggested that opponents of Murthy are somehow responsible for the president's Ebola problem. "POTUS would not need an Ebola czar if the NRA, Republicans had not blocked his Surgeon General appointee," the liberal columnist E.J. Dionne tweeted on October 17.

Dionne left out just one important player: the Democratic majority that controls the United States Senate.