Russia is blocking a Euro pean attempt at the UN Se curity Council to condemn the Syrian bloodbath and is widely expected in the next few days to kill it, if it needs to, by imposing a rare veto.

Thus ends the recent (if short) run of arguably effective UN resolutions on the Middle East — successes that some claim justify President Obama’s emerging doctrine of always uniting the “international community” behind issues America cares about first, and only then acting on them.

There was also good news yesterday: America convinced the Vienna-based International Atomic Energy Agency that Syrian violations (building a secret nuclear facility, which was destroyed by Israel in 2007) deserve a referral to the Security Council. The bad news: Once the case gets to New York, Russia will likely kill that attempt to punish Syria, too.

Not to worry: The deep divisions in the UN “community” aren’t likely to determine Syrian President Assad’s ultimate survival or fall.

But why did the Obama administration, normally a UN enthusiast, opt this week to hide behind the backs of Britain, France, Germany and Portugal, and lead from even farther behind than it normally does?

An example of just how low-key US diplomacy was: Brazil’s Foreign Minister Antonio Patriota said yesterday that the views of Lebanon on Syria were “crucial” in forming his country’s opposition to the proposed resolution.

I had to ask Patriota about America’s input before he finally recalled that, oh yes, on Wednesday he also talked about Syria with Secretary of State Hillary Clinton.

But the ultimate decision by Brazil — Latin America’s most influential country, with which our relations were recently “reset” — apparently hinged less on Clinton’s advice than on that of Nawaf Salam, the UN ambassador of Lebanon, a tiny country so fearful of its formidable Syrian neighbor that it needs Assad’s OK before naming any top government officials.

Again, Brazil’s decisions, indeed those of the entire Security Council, rarely amount to much in the real world, except when the powers that can actually do something feel the need for an international stamp of approval.

And the Europeans’ proposed resolution is so weak it doesn’t even contain mild sanctions on Syria, let alone any other punishment. (The proposal actually calls on Damascus to “launch” an investigation into possible human-rights violations. Perhaps Assad should hire O.J. Simpson to search for the “real” Syrian killers?)

British Prime Minister David Cameron “warned” earlier this week that if Russia or others on the Security Council vote against the resolution to condemn Syria, “That should be on their conscience.” Sorry: The Assads of this world aren’t too impressed by conscience.

Neither, for that matter, are the likes of Russian President Dmitry Medvedev or Chinese Premier Hu Jintau, who focus far less on morality and more on cold calculations of their interests.

Russia, mostly, wants to avoid seeming to betray its besieged Mideast friends (as America abandoned Egyptian President Hosni Mubarak). Syria has been Moscow’s closest ally in the region since the 1950s, and Russia maintains a naval presence in the Syrian port of Latakia, a strategic eastern Mediterranean spot.

But mostly UN diplomats are wondering why America was so inactive on this week’s Syria diplomacy. Why did our UN ambassador, Susan Rice, seem more enthusiastic about highlighting America’s success in uniting the world against AIDS (there’s no pro-AIDS voting bloc at the UN) than about backing the Europeans against Syria?

Obama’s aides, I’m told, are divided — with some now advocating a public and unequivocal call for ending the Assad regime, and others fearful of chaos if the Damascus dictator goes. Some still believe Assad may yet emerge as a “reformer.”

Plus, the administration is also wary of breaking up whatever agreement there is among world powers about the increasingly complex Mideast “Arab Spring.” Mostly, Washington wants to maintain the show of unity among the three top powers: America, Russia and China — a façade that would shatter if the latter two vetoed a US-backed Security Council resolution.

Whatever: The end result is a very incoherent, indecisive and hesitant US policy on one of the hottest Mideastern flashpoints.

Once he decides what he actually wants to do about Syria, Obama may want to first articulate it clearly enough for Assad to understand. More importantly, America might then be able to act in a way that actually makes a difference on the ground. beavni@gmail.com