I can hear all the objections from right and left. Let me address a few. Much of this oil and gas will simply be substituted for (banned) Russian energy, so it is unlikely to cause net-higher emissions. There is even an environmental benefit. U.S. gas leaks less methane than Russian gas, and U.S. oil production is also less environmentally harmful than Russian production. In many places, the increase in natural gas could mean countries like Germany could use less coal, a dirtier fuel in nearly every way. In fact, the best way to cut carbon emissions in the short term — with current technologies and at scale — is to replace coal with natural gas.
A few points here--
The oil industry does not turn on a dime. Opening up more leasing here is not going to be producing substantially more fossil fuels anytime soon, and the oil industry is already attempting to do more domestic production because of the skyrocketing prices - and since they're sitting on huge tracts of unused leases, they already have the assets to start exploiting. The calls for more domestic production are mainly for future profits, and maybe some changes to the futures markets (i.e. market spirit animals).
US natural gas to europe means LNG (liquified natural gas), which is a very energy-intensive process. Since we don't have hard figures for russian leakage (though it certainly seems to be high) hard to say if it's guaranteed that US LNG is worse GHG-wise than russian normal natural gas, but it's also not guaranteed better. Also the case that we'd likely need to construct more LNG terminals both in the US and in Europe, which isn't necessarily a quick or cheap process.
Replacing coal with natural gas is good in the short term, yes, but medium and longer term is less sure. There's a lot of concern (some of which is arguably already happening) that natural gas will simply replace coal/oil as the vested interest, and the pivot to actually clean fuels will take too long to avoid some of the even more frightening climate scenarios. A lot of coal infrastructure in the US is aging and in need of replacement; replacing that with natural gas assets may effectively lock them in for their decades-long service life, even setting aside the politics.
Further, the US (and even Europe!) ending consumption of russian oil does not necessarily mean that russian oil won't be produced or sold. There are plenty of countries in the world with demand and less qualms purchasing from Russia, though this is admittedly more of a thing for its oil than its natural gas (which is harder to ship around easily).
All that said, I agree it's not an easy situation. Probably the main point I have is that there
isn't any quick way to reduce the global economic consequences of cutting off russian oil and gas, and that we shouldn't kid ourselves that selling new oil and gas leasing is going to change that in the next year or few.
(relatedly, Biden announced the ban earlier today and congress is likely to legislatively formalize it by the end of the week)
As to Trump/Putin, just a note that it's not as if Putin was being peaceful during the Trump years. The 'civil war' in Ukraine was raging all that time, even as Trump was sabotaging aid to Ukraine in order to satisfy his personal paranoia. More broadly (and thankfully), a fair bit of the US international apparatus at that time was functioning much the same as it had been under Obama (and before), and was able to resist Trump's... whatever he was doing.