Army Chief of Staff Matthew Cox warns Russia that the US "will stop you and we will beat you harder than you have ever been beaten before." You can read about it here:
Time for a reality check:
(1) According to the Heritage Foundation, the state of the US Army in 2016 is "weak", while the AF, Navy, and Marine Corps are rated "marginal".
The US Army currently has fewer than 32 Brigade Combat Teams (less than 100,000 troops) available for combat, and not all of them are ready for deployment against Russia.
You can read the rest of their assessment here:
(2) When Germany invaded Russia in 1941, it ultimately committed 4 army groups consisting of 3.7 million troops to the effort (source - https://en.wikipedia.org/wiki/Operation_Barbarossa).
Although the Germans made huge initial gains, ultimately the Russians smashed the German armies and drove their remnants all the way back to Germany.
During the same period US forces which invaded Europe faced mainly reserve troops, young boys, and old men, since the Germans had committed their best forces to the Eastern Front. We really didn't beat anyone of note, at least not in the European Theater.
(3) Without air superiority, US forces are highly vulnerable to attack. The Russians possess state of the art AA and ABM systems, so it's very unlikely the US could achieve air superiority in any US-Russia engagements.
(4) During World War II, Russian infrastructure was smashed while the US remained unscathed. It's not likely the Russians will allow this to happen again. Should they wish to bring the battle to North America, the chief weapons they possess to do this are nuclear armed missiles. So, while the US Army tries to slug it out with the Russkies in Europe, our cities back home may be reduced to radioactive rubble.
I don't know what General Cox has been smoking, but I doubt things will go as well as he predicts.
And even if they do, a lot of people will die and several countries will be smashed for little or no meaningful gain.
None of this has to happen. And We The People should make damned sure that it doesn't.