Well, you'd have to ask, was there a reason they took Alaska? They might have a good reason. Maybe they think there was something wrong with how we bought it from them. They might feel we took advantage of them. I mean, wouldn't you sympathize with someone that felt taken advantage of? They'll have a good reason. Russia wouldn't do anything on a whim. Not just to enrich themselves or establish a beachhead for the rest of the continental Americas; surely not.
Of course... even if it were a beachhead... Russia might have a good reason, and we like Russia, they're good friends. Maybe we should join together in some kind of union...
/s
PS: If someone was nodding their head along with the above, just know you're on the wrong side of... well, everything.
The United States has a history of organizing campaigns to crush terrorist organizations. A month ago, the United States designated six cartels as terrorist organizations, which prompted Mexico to issue a warning about the United States attempting any sort of invasion or incursion. This is also occuring in tandem with the current President of the United States going on about taking Greenland and Panama, and how Canada should be part of the United States, which was also interpreted as a suggestion of a hostile takeover.
And then there are reports of them having been mulling options since November, talk of it by political candidates in 2023, talk by sitting members of Congress and even legislation introduced in support of it within Congress.
Not so curiously, these acts have been exclusively done by Republicans, also known as the Right-Wing.
Of course, if you could show that Democrats were as keen on the idea of invading Mexico, then calling it right-wring would be in error.