Finally -- after way too long spent grovelling on the world stage -- Donald Trump didn't chicken out. For the first time in the nine months he has been in office, Trump actually moved to punish Russia. Hopefully, this represents a shift in his thinking that will be hard for him to easily reverse. Because for the first time, Trump is no longer acting like Vladimir Putin's lapdog.

Trump just announced sanctions on two of Russia's biggest oil companies, Rosneft and Lukoil. This will prevent them from access to Western banking systems, and the sanctions theoretically will extend to anyone doing business with them anywhere in the world. Such sanctions are not a new thing -- Joe Biden, on his way out of office in January, slapped sanctions on two other large Russian oil companies (Surgutneftegaz and Gazpromneft). So Trump's move is really an expansion of the previous strategy of sanctioning the Russian oil industry.

The devil, however, will be in the details. Such sanctions -- especially the secondary sanctions on other companies and countries that do business with these Russian oil giants -- have to be rigorously enforced. The Biden sanctions from January have only had a limited effect because of "lax enforcement of the sanctions" under Trump. And not only has Russia adapted to the situation, but completely strangling the flow of Russian oil would have an impact on the global oil market as well:

Russia [has] become adept at evading restrictions by using a fleet of hundreds of old vessels uninsured by Western companies and by conducting transactions through buffer companies in third countries. And because Russia accounts for about nine percent of global oil sales, any restrictions against its exports would cut supply and push prices up, creating incentives for further sanction evasion.

Oil prices worldwide "rose sharply on Thursday in a sign of the sanction's potential potency," which is going to hurt American consumers (along with everyone else in the world). So there are conflicting political forces at play here for Trump.

But at the very least Putin is not exactly happy about the situation, saying in an interview: "This is an unfriendly act toward Russia, and it doesn't strengthen relations between Russia and the United States that only began to get restored. But no self-respecting country and no self-respecting people ever decide anything under pressure." That last sentence is ironic in the extreme, when you consider that this is exactly what Putin is trying to do to Ukraine.

Russia has famously been described as "a gas station masquerading as a country," since it is so reliant on its sales of oil to the rest of the world. Fully one-forth the government's budget comes from the oil industry -- not quite "just a gas station," but still of major importance. Curtailing the sales of Russian oil and energy products to the rest of the world will hurt the Russian economy, it's just a question of: "How much?" at this point.

One example of this is that the new sanctions may achieve what Trump stated his goal was when he doubled the tariffs on India, ostensibly to punish it for buying Russian oil. No such pressure was applied to China (which buys even more Russian oil), and the increased tariffs have so far failed to stop Indian companies from continuing to buy discounted Russian oil. But the new sanctions -- if they are vigorously enforced on the buyers of Russian oil -- could alter the situation to the point where the Indians go back to buying most of their oil from the Middle East.

Europe also announced new sanctions against Russian energy products this week, including a phased-in ban on importing Russian liquefied natural gas. Europe is also considering a much bigger step: using the roughly $200 billion in frozen Russian assets held in Europe to finance Ukraine's war effort. This would be arranged as a tricky diplomatic fiction (the money would be "loaned" to Ukraine, but they'd only have to pay it back if Russia paid them war reparations in the future, which doesn't seem very likely). Such an influx of money could be a game-changer for Ukraine, as it would allow them to keep fighting for years.

Ukrainian leader Volodymyr Zelenskyy welcomed the move from Trump, saying, "We were waiting for them -- God bless, I hope they will work." But it wasn't what he really wanted to hear, when he met with Trump in the White House last week. What he really wanted was Tomahawk missiles, which he could use to strike deep into Russian territory. Ukraine has already had a lot of success in targeting Russian oil facilities (such as refineries), and the Tomahawks could certainly help this effort. This strategy has already been so successful, in fact, that gasoline rationing is now a reality in regions of Russia.

So far, Trump hasn't agreed to make Tomahawks available to Zelenskyy. But now he should realize that the threat is very real to Putin -- who knows full well this would boost Ukraine's ability to inflict economic harm on his country. Putin was so scared Trump was going to greenlight sales of Tomahawks to Ukraine last week that he picked up the phone and talked to Trump for over two hours, on the day before Trump and Zelenskyy were scheduled to meet. As usual, Trump then started parroting the Russian line and immediately backed off any offer of providing Tomahawks.

Which is why the news that Trump has finally acted against Putin is so surprising (and welcome). This is the first time Trump has done anything punitive against Russia, in his entire second term in office. While it is still an open question how robustly these sanctions will be applied and policed, it is at least a symbolic diplomatic victory for Ukraine.

Last week, during their phone call, Putin offered to hold another summit with Trump, in Hungary. Trump seemed eager to do so, since he loves the pomp and ceremony of such events. But then after a testy exchange between top diplomats from both countries, suddenly the summit was off. Perhaps Trump got annoyed at Putin for not just doing what Trump told him to do (accept a ceasefire at the current battlelines)? It's certainly possible. Putin, to date, has not done anything Trump wanted him to do, so perhaps Trump's patience finally just came to an end? Whatever is behind the move, it is indeed a welcome development. Because finally -- finally! -- Trump is acting like a president who doesn't just do Putin's bidding in all things. Finally Trump has begun to push back. We'll see if this develops into further actions which will aid Ukraine, but at least it is a good first step.

-- Chris Weigant

Follow Chris on Twitter: @ChrisWeigant