I forgot about Alaska, but there you have your new flashpoint. In TL-191 it is an underdeveloped part of a Tsarist Russia, that won its civil war against a proto-USSR. Maybe some 80.000 Russians live here. TL-191 only goes up to 1945, so we can either assume that it remains as it is, or go with the fanfic After the end which has the US invading Alaska by 1948.
If we go with Tsarist Alaska, then Tsarist Russia is gone, and the US is the "ally of the enemy". If the Soviets move quickly or play their cards smart, then it could easy gain Alaska. OTOH, TL-191 USA could also make it a protectorate.
Well, TL-191 US claims ownership of UK/Fr Caribbean possessions, so there is that for a point of conflict. Or are we considering the Caribbean as part of the NA-continent? In which case, you have the same problem with UK/Fr suddenly losing their colonies to the US.
The policy of TL-191 USA to prevent Russia, UK and France from developing nuclear weapons is also an issue, and one possible way for Dewey (or who is the US president by 1950) is to demand that the UK and Russia give up their nuclear weapons.