Law and order. Except for Putin. He totally gets to annex parts of other countries and meddle in our elections with impunity.
If we look at the actions, instead of just words, Trump has arguably been clearly more damaging to Russia than Obama.
1. Trump approved arms deliveries to Ukraine, something Obama adamantly refused to do.
2. Under Trump's presidency the sanctions have gotten much tighter.
3. Trump has allowed oil drillings on ecologically sensitive areas, which has increased the US oil producing potential and thus weakened Russia's position on energy markets.
4. Trump has publicly denounced the New START treaty and rebuked Putin's offer to continue it after 2021.
5. Trump substantially increased the US defense budget and wanted to massively bolster the US nuclear arsenal. Indeed he directly stated that he wants an arms race and Russia is the only country with a nuclear parity with the US currently.
6. Trump broke the Iran deal, which Russia helped to achieve. In fact Obama thanked Putin publicly for it and Putin has continued to call for the US to respect the treaty. An US attack on Iran would likely be pretty awful for Russia, despite giving a spike to oil prices, as Iran plays a crucial role in enabling Russian presence and operations in Syria. (Russia tranfers its combat aircraft to and from Syria for example through Iranian airspace, and there are no realistic alternatives)
7. Trump twice attacked Russian ally Syria and continues to occupy Syrian territory.
All these things doesn't prove that there wasn't anything funny going on between Trump and the Russians, but it would probably be healthy to be cognizant of this side of the story too.
Just to make an obvious point about punishing countries.
The world (or any elements in the US internally) didn't sanction Bush for committing far greater and more destructive crime in attacking Iraq than anything done by Putin. Nor did it punish Obama for destroying Libya and criminally supporting illegal armed groups in Syria, flaming the awful situation into even greater bloodshed.
Sanctioning Russia has nothing to do with upholding the law or punishing bad behavior. It has to do with weakening a competitor. We know this for fact, because the same behavior gets totally different reactions depending on the actor. Just compare how the US treats Saudi Arabia and Russia. The US actually actively supports the destructive Saudi attack on Yemen. And this isn't any new development either. In fact Russia itself has been consistently sanctioned since the times of Russian Empire. Good example is of course Saddam Hussein. The US supported him through the worst crimes (massively destructive aggression against Iran and chemical attacks against the Kurds, the US actually publicly blamed Iran for the chemical attack, despite knowing that it was Saddam (no great mystery why the Iranians don't like America very much)), and only turned against him after he crossed the US itself by attacking a US ally.