Those who now claim that three Russian S-300 air defense battalions (equipped with the export version of the S-300VM – the “Antey-2500”) or even thousands of Russian-made MANPADS can stop the US simply don’t understand warfare in general and air-defense operations specifically. What these folks do is to take a few figures about, in this case, the theoretical capabilities of the Venezuelan S-300s and then compute how many aircraft/missiles these systems could shoot down. That is not how air defenses work.
The sad truth is that absent a multi-level integrated air defense system like Russia has, air defense operations typically turn into a simple numbers game: X number of defensive missiles vs. Y number of attackers. Keep in mind that effective EW (especially SEAD) will dramatically reduce the effectiveness of any air defenses. The same applies to whatever number of Su-30 or even Su-35s Russia might deliver to Venezuela.
Now, look at a map and see for yourself: Venezuela is literally in the US’s backyard (at least in military terms), and the US can bring HUGE numbers of whatever it wants (missiles, bombs, SEAD aircraft, etc.) to the fight. Not only that, but the Venezuelans lack any real counter-attack options, which means that Uncle Shmuel can fire off as many missiles as he wants for weeks and months without ever having to worry about a counter-strike.
It is only political factors protecting Venezuela from an overt US attack, not military factors. The latter are not irrelevant, of course, and I discussed them here. In military terms, Venezuela is a sitting duck which might be able to deter a ground operation, but which can do nothing against US standoff striking capabilities, at least not against a determined US effort. Against a pretend-strike, like what the Israelis and the US did in Syria, the Venezuelans could probably meaningfully degrade the number of US bombs/missiles reaching their targets. But that is all they can reasonably hope for.
Source: The Unz Review