@Cernel I believe it may be a bit different situation between combat and politics. I found recently that for combat, if you are actually selecting casualties, the casualty selection menu does not highlight the "okay" button. Meaning, the scenario of 1 hit between 1 bomber and 1 infantry - you will never space bar click through that. I think this takes away most of the reason stated for removing the space bar confirm on casualties. I found that on single player, if the game behavior is different with other options or game play types, I would be curious to know about those cases, but I think it may be across the board the final casualty selection requires a mouse click.
For the politics panel confirmation - maybe we should look at adding a confirmation dialog if an action is selected. IIRC, when looking at this some time ago, it was not trivial funny enough to remove the space bar activation, but that might have changed - it's another option. Really we should be looking at the two situations on their own, they are their own code paths and would have their own fix applied respectively.