Russia provided Iran and Venezuela with many weapons.
The US demanded that Iran negotiate, Iran agreed, and, while Iran figured they were safe while negotiating with the US, Israel first, and then the US attacked Iran.
Israel had many Iranians telling Mossad, the CIA, and MI6 almost everything they needed to know: the initial Israeli attack killed most Iranian generals and Nuclear Science Professors in their homes, which were known to Israel, and also destroyed the Iranian air defence system with an EMP attack, so they knew exactly where the computers that controlled the Iranian air defences were located.
But Russians got the Iranian air defence system working again in less than 24 hours, so the second Israeli strike didn't go nearly as well as planned. And the Iranian response? Reported as totally ineffective by all the Israeli/US/UK/EU reporters, and totally effective by all the Iranian and Russian reporters. (So not clear at all what really happened.)
If the Iranian/Russian version is to be believed, after the damage from the initial strike was repaired (by naming new generals and having Russia repair the air defence system), the Iranians did massive damage to Israel and the US military base in Qatar.
If the US/Israeli version is to be believed, the US/Israeli attack completely destroyed the Iranian nuclear bomb development programme (which Iran lie did not exist), with no damage to Israel or the US base in Qatar, so now Iran can never again threaten Israel or US assets in West Asia.
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But what about Venezuela?
It is obvious that all the Russian air-defence systems in Venezuela were easily destroyed by the US, who were then able to land dozens of helicopters full of US military, who were able to capture former president Maduro and bring him to the US, where he is now an accused (and soon to convicted) narco-terrorist, and his wife, who will be accused and convicted of the same crimes.
Net??? a) Russian air-defenses are useless against the US military, who could easily arrest Putin and Xi as narco-terrorist war criminals whenever they want, using exactly the same method they used to arrest President Maduro and his wife; or b) Venezuelan have a lot of CIA/MI6/Mossad agents who paid corrupt Venezuelans to give them all the details of where the Russian anti-aircraft systems were located, so the US could easily destroy all those systems, and also told the US where Maduro and his wife were hiding, so dozens of US helicopters could drop a huge force to kill all Maduro's guards and arrest Maduro and his wife.
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So, at this point, if one believes the US/UK/EU version of events, the US could very easily arrest Putin and Xi for war crimes and make the government in Taipei the legitimate government of all China and some good Aryan in the Ukraine the legitimate ruler of Russia.
Or, if one believes Russia/PRC propaganda, the US are losing in the Ukraine, which will soon be divided into a Russian part and an Aryan part, and the Aryan part will be much smaller than the former Ukraine, and too weak to threaten Russia.
Venezuela remains a question, since it is in the Monroe Doctrine area, close to the US and all the US weapons systems and very far from Russia and the PRC. President Trump has announced that the US will insist on a Venezuelan puppet who will do everything the US demands, starting with the return of all Venezuelan oil and other resources to the rightful American oiligarchs, who will pay a very tiny group of compliant Venezuelans a lot of money to let the US take everything, and leave the vast majority of Venezuelans with nothing. And many believe the Monroe Doctrine will prevail in Venezuela, so Russia and the PRC can do nothing about it, and won't dare to even try.
But the PRC have invested a lot in Venezuela, and they desperately need the oil. And if they let the US have Venezuela, Iran will be next. The US would love to have all the Iranian oil, but if it is not possible to overthrow the Ayatollah and return to the days of the Shah (before 1973, when the Shah did a Mossadegh), Israel are ready to nuke Iran to eliminate the Iranian threat to Israeli dominance of West Asia, and then no one will be able to use the radioactive oil. And the US will settle for cutting the PRC off from all oil, either by having all the oil under US control (best case scenario), or having the oil destroyed so no one can use it (not so good, but destroying the PRC economy would be worth it).