lets say during the french invasion of Russia Alexander is killed what happens next does the Russians continue fighting or do they surrender or elect a new monarch to lead them?
Constantine died from disease brought by Russian troops send to Poland to fight November Uprising. As Tsar Constantine would likely avoid this fate, although it is possible, that he'll be long dead by this time, assassinated like father. Constantine was not 100% sane, he was also biggest polonophile among Romanovs, man, who renounced his rights to Russian throne to marry Polish woman.There is an orderly succession to his brother Constatine who doesn't renounce his rights until 1823. Nicholas I would have been only 16 and Constatine has no legitimate heir (he might in the TTL though) so its likely that Nicholas i would still become Tsar but later- 1831 instead of 1825
Constantine died from disease brought by Russian troops send to Poland to fight November Uprising. As Tsar Constantine would likely avoid this fate, although it is possible, that he'll be long dead by this time, assassinated like father. Constantine was not 100% sane, he was also biggest polonophile among Romanovs, man, who renounced his rights to Russian throne to marry Polish woman.