I wrote this on another thread about two weeks ago, when a similar debate on Patton and the Russians cropped up. I hope this helps you realize just how badly Patton would have been beaten.
(I have taken the liberty of copying the whole thing, so it might lose something in the context of this debate):
It was evident by the time of the invasion of Okinawa (April 1, 1945) that the American public was beginning to tire of war. Truman (eho became president shortlay after the invasion) was already beginning to hear the first rumblings of the "Stop the War NOW" crowd. It was one of the major factors in the decision to use the atomic bomb against Japan.
The US Military force that invaded Western Europe in June of 1944 was an unbalanced force, with too few infantry units and whole lot of specialized units that had dubious value on the battlefield. In fact, it was Patton who cannibalized these non-infantry units in 1944 during the Battle of the Bulge and the crossing of the Rhine because he lacked infantry. The infantry problem had become so severe by late 1944 that those previously considered 4F were now considered eligible for service. One of them (Eddie Slovik) was executed on Eisenhower's orders for desertion during the fighting in the Hurtgenwald (precursor to the Bulge). Three entire infantry divisions had their total casualty numbers exceed 100% (meaning even the replacements got chewed up at a prodigious rate) during action in the Hurtgenwald (winter 1944).
By 1945, 16 million American men were in uniform (in all services), and there simply were no more soldiers to be had.
As for the Allies, the British were exhausted by six years of war, and most certainly would have collapsed had it not been for the Empire, in particular, Indian troops. India was promised independence by the British just as soon as the war was over, and asking Indians to fight Russians for political reasons which meant nothing to them, was absurd. The Japanese were still knocking on India's door in Burma and that's where Indian troops were needed: at home. The British could provide no help.
The French Army was entirely equipped by the Americans, and likewise, was in no shape to fight. In addition, the political situation caused by Churchill's, FDR's, and Eisenhower's (justifiable) snubbing of DeGaulle from 1942 onwards, made French alliance a shaky proposition.
We won't even get into the problems inherant with the Chinese as allies. The best the Chinese could manage to do in 8 years of war was to tie up 2 million-plus Japanese troops just by standing in front of them, while allowing their country to be overrun (and their population slaughtered), and fighting amongst themselves. Chiang would not have been a good ally, either.
Rearming the Germans would have been political suicide in the United States. We had just sacrificed hundreds of thousands to defeat the Nazis, it would not do to rearm them, even if the Russians were the threat Patton (and many others) believed them to be. Good will towards Russia and "Uncle Joe" was rampant in this country, as well. We could not turn on an ally and use the former enemy to help us.
That's the first problem; there were no men to continue the fight, and no ally capable of supplying them.
The second problem is logistics.
Patton's Army in 1944/45 was operating at the end of a 4,000 or so mile long logistic train that ran all the way from the United Sates to Germany proper. The allies had serious problems in getting ammunition and supplies from the French coast to the interior of France and German border, the problem would have been astronomically more pronounced by extending that supply line to Poland or Czechoslovakia.
Assuming Patton had the resources (men) to fight, keeping them in beans, boots and bullets would have been a nightmare. Even as late as 1991, the US Army had not solved the problem of getting supplies to the front (even with airlift, heavy sealift and helicopters) in Iraq, which is one reason why the ground war was so short: the front-line armored units were beginning to run out of fuel after those initial 100 hours. To quote, ironically, a Russian General (Rossikovsky) "Amateurs discuss tactics, professionals discuss logistics".
Patton, even assuming a fully-manned army, would have had serious trouble keeping them well-equipped and supplied. The Russians, on the other hand, had full access to the oil fields of Ploesti, the Caucasus and with a weakened Britain, could easily have advanced on the Middle East (much like Hitler attempted). The Russians also had interior lines of supply: Patton's suplies have to cross the Atlantic and half of Europe, the Soviets are, in effect, right next door to their own sources of supply.
Next problem: Relative quality of equipment. The Sherman tank was undoubtedly the WORST tank any nation sent into battle (with the exception of the Japanese) in the Second World War. It's only saving grace was numbers: it could be surged produced on demand. It's only improvment was British: the incorporation of the 17-pounder gun (90 mm, I believe). The Sherman, which suffered such horrendous losses against even the earlier-model German Panzers, would have suffered even worse by the numerically- and technically- superior T-34's and Stalin tanks against which it would come up against.
The American specialty, in regards to fighting the Germans, was artillery. American artillery litterally saved tens of thousands of American lives on the battlefield because it was available in sufficient numbers, had a sophisticated fire-control regime, and was of generally better quality than it's enemy counterparts (except for the German 88, of course). For every gun the Americans could put in the field, the Russians could put five (the opening assault on Berlin by the Russians featured upwards of 20,000 artillery pieces, of all types).
There was a situation in early 1945 where the supply of ammunition for American artillery had virtually dried up because of commander's ability to use it abundantly and because a short-sighted, cost-cutting Congress (with the end of the war near), cancelled the contracts that supplied American Artillery with it's shells.
It is intersting to note that almost 50% (I beleive it's greater than 40%, but leaning towards 50)of all battle casualties in WWII were caused by artillery. In this regard, Patton was outgunned, and undersupplied.
With regards to Air Forces, while the US did have the P-47, P-51, and P-38 (best fighters of the war), the B-17, 24 and 29, and a tactical and strategic air force second to none, the Russians did surge 12,000 (if I recall) aircraft into Western Europe upon beginning the Vistula-Oder campaign that finally cracked the German defenses. Qualty-wise, the Americans have the edge, but quantity often has a quality all of it's own, and many of those Russian aircraft were comparable in performance to their German counterparts.
Next in line is geography. Assuming Patton could overcome his manpower shortages, material inferiority, poor tanks, more or less even air forces and the logistial nightmare, he would still have to contend with geography. Patton would eventually, if given free reign, have to enter the Soviet Union and faced the same problems the Germans did: there would never be enough men to present a coherent front against the Russians. There is the Pripet Marshes (known to the Germans as the Wermacht Hole) more or less sitting in the middle of the Soviet Union, and impassible to armored or mechanized forces, in effect, splitting your front in the face of the enemy. We won't even get into the weather, the numbers of rivers that need to be crossed after passing the Ukranian steppes, the vast landmass of the Soviet Union, etc. Patton could never keep his army in the field with all the holes that would have naturally opened in his front lines.
This, more than anything else, explains why the Germans lost in Russia -- they could never truly hold what they took. General Winter and Stalingrad only accelerated the process.
Finally, if your argument becomes "yeah, but we had the atomic bomb", I remind you that it took four years and $2 billion to build TWO weapons (really three, one was consumed in testing), and the scientists who worked on it were not even certain it WOULD WORK WHEN FIELDED. That is not to say that because the ones used against Hiroshima and Nagasaki proved the concept that every bomb churned out afterwards would work, or work as effectively.
Also, Japan, unlike Russia, is an island nation, lacking in resources, which can be strangled by controlling the surrounding seas. The Japanese were defeated (in a real sense)by American naval domination of the Pacific and destruction of it's merchant marine, not the atomic bomb. The Japanese had been seeking peaceful resolution of the war long before the bombs were dropped. The US Navy once estimated that Japan could be finally forced to surrender by virtue of a continued American naval blockade, but that such a blockade would have to stay in place way into 1946.
Certainly not doable in the face of kamikaze attacks and a public wanting the troops to come home.
Russia could not be weakened by blockade, it could not be starved into submission, it did not lack resources. The only way Russia could be defeated was on the ground, and Patton (or any other commander you could think of) would have been very hard-pressed (and doomed to failure) to even try. Atomic bombs would not work in Russia (wide-open spaces, huge population, abundance of natively-held resources) the same way they did in Japan (starving nation, isolated from supply or reinforcement, crowded into four relatively small islands).
Patton would have failed UTTERLY and COMPLETELY.
(Here, the other end of this exchange tried to compare Patton to Alexander the Great)
The comparison between Alexander and Patton is unfair: Darius was not a westerner, steeped in the traditions of western culture and politics, mass production, and annhilation warfare. Patton's potential enemies WERE, every bit as much as he was (and quite frankly, perhaps BETTER than he was). Darius' loss to Alexander was not so much a military victory as much as a matter of superior Greek civilization meeting a more primitve, slave-based society. Alexander's army was there VOLUNTARILY, for reasons they believed in, while Darius' army was certainly not.
And I'm sad to say it, but while George S. Patton himself was a colorful and wonderful character, he was sorely lacking as a commander come 1945. After the slapping incidents in Sicily, and being kept from command for over a year, Patton toed the Eisenhower/Bradley line that infantry, not masses of armor charging the enemy, was going to win the war,and that politics and public relations were just as important as his tanks. His last campaigns in Europe are certainly uninspired, and he shows all the signs of having been muzzled by Ike and Brad.
Patton would have lost so severely that his name would be a curse in our day and age.