Republican panic at the prospect of facing Hillary Clinton in the 2016 presidential race has suddenly reached Godzilla-nearing-Tokyo proportions.

The election is more than two years away, and Clinton hasn’t even decided whether to run. But none of this seems to matter to the GOP strategists and spinmeisters who are launching the whole arsenal at her — smears, innuendo, false charges. Already, they’ve moved beyond distorting her record to simply making stuff up.

As these damp squibs clatter harmlessly to the ground, it’s useful to remember that Clinton has seen it all before. And I mean all . Anyone who thinks she’ll be rattled or intimidated hasn’t been paying attention the past few decades.

If anything, Republicans are succeeding in raising Clinton’s profile and perhaps making her a more sympathetic figure. This was certainly the impact of Karl Rove’s smarmy and unfounded recent speculation about her health.

In December 2012, Clinton, ill with a virus, fell in her home and suffered a concussion, spent three days in the hospital, wore corrective glasses briefly for double vision — meanwhile going back to work as secretary of state — and made what to all appearances was a full recovery.

1 of 9 Full Screen Autoplay Close Skip Ad × The next Democratic leaders? View Photos In her first monthly column for The Post, MSNBC host Rachel Maddow names nine politicians who could be the party’s future national faces. Caption In her first monthly column for The Post, MSNBC host Rachel Maddow names nine politicians who could be the party’s future national faces. Sen. Elizabeth Warren of Massachusetts The former Harvard professor’s staunch populism on issues ranging from financial regulation to expanding Social Security has made her a darling of the progressive wing of the Democratic Party. Though she insists she is not running for president in 2016 , many liberals hope she will provide a more progressive alternative to Hillary Clinton. Joshua Roberts/Reuters Buy Photo Wait 1 second to continue.

Rove grossly inflated the episode to “30 days in the hospital” and “traumatic brain injury.” Appearing later on Fox News, he insisted that Clinton’s health “is going to be an issue.” The Clinton camp responded that “there are no words for this level of lying” and gave assurances that Clinton is in perfect health. But Rove’s intent was clear: Fabricate an “issue,” toss it out and see if it sticks.

Sen. Marco Rubio (R-Fla.), an all-but-announced candidate for the GOP nomination, was even less subtle, claiming that Clinton’s term at the State Department was characterized by “massive failures.” He mentioned her inability to get Russian President Vladimir Putin to behave like a model citizen — something that no secretary of state, as I recall, has managed to do. Oh, and he mentioned Benghazi.

Benghazi, Benghazi, Benghazi. . . . Get used to that name, because you’ll hear it a zillion times if Clinton runs. We’ve seen from her appearances before Congress, however, that she answers questions about the tragedy forcefully and well. I wouldn’t bet my political future on the dubious prospect that she’ll meekly go away if the Benghazi chant is raised to a din.

Given that Clinton’s actual record at State is unpromising for Republicans to attack, there is now an effort to foul the atmospherics of her tenure. Most far-fetched is the suggestion that Boko Haram might not have kidnapped those nearly 300 Nigerian schoolgirls if Clinton had pushed — against the advice of diplomats, experts and the Nigerian government — to designate the group as a terrorist organization. There is no basis for this unlikely notion. Boko Haram has been on the terrorist list since November, and it didn’t stop them.

If she runs, this won’t be Clinton’s first rodeo. It won’t be the first time that bitter opponents have spun a false history out of whole cloth and tried to pin it on her. The paranoid fantasy over Vince Foster’s suicide comes to mind.

The reason for all this panic is obvious: Republicans fear that if Clinton runs, she’ll win.

Polls consistently show her beating all hypothetical GOP opponents, both nationally and in key swing states. New Jersey Gov. Chris Christie was competitive, for a time, but the George Washington Bridge scandal has sent his numbers south. Jeb Bush, if he decides to run — and manages to win the nomination — might have the kind of crossover appeal that would give Clinton trouble. But at present, none of the other frequently cited contenders seems much of a threat.

Nothing is guaranteed, of course. You will recall that Clinton was supposed to steamroll her way to the 2008 Democratic nomination, only to have the junior senator from Illinois get in the way. In 2016 she might well face a challenge from the party’s activist left.

If Clinton should get the nomination, her Republican opponent — no matter who it is — would be no pushover. But the possibility of electing the first woman as president would likely stoke the enthusiasm of Democratic voters to the point where the party’s structural advantages — overwhelming support among minorities and women — come into play. Clinton might win big.

Hence all the premature mudslinging, which reeks of desperation. Republicans hear the sound in the distance. They feel it in their bones. Stomp. Stomp. Stomp.

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