Putin is seeling nuke parts to Iran and missiles to Syria because Putin believes that with the help of Iran and Syria he can turn Iraq into our "Afghanistan" the way the USA and Pakistan and Saudi Arabia and the mujahadeen turned Afghanistan in "the USSR's Vietnam."
Putin wants us pinned down in the Middle East - which means he wants Iraqi democracy to fail, and he wants the Israeli-Arabs peace process to fail, too. That's why he's aiding Iran and Syria.
In other words: peace and freedom in the Middle East are not in Putin's interest. Additionally, if Putin can help Noth Korea muddle things up in Asia, he will. Putin also wants high oil prices (which greatly benefit Russia), as much as he wants the American military to get bogged down in as many places as possible.
In a nutshell: Putin is an authoritarian seeking to re-establish Russia's hegemony along the borders of the old USSR. He is no longer a trustworthy partner in any shape, manner or form. He is an adversary.
WHY DID THIS HAPPEN? Well, we beat him on the ABM, and in Georgia and Ukraine, and he is PISSED OFF and doing whatever he can to "eff us up." And he is a greedy authoritarian with no meaninglfull opposition or checks on his greed. THAT'S ALWAYS DANGEROUS A THING!
Bush must make it clear to Putin that we are onto his game, and will take it to him. How? By winning Lebanon, Syrai, and Iran - AND North Korea.
And by fomenting an Orange Revolution in Russia! We must identify and aid a true democratic movement in Russia. ASAP!