Because as normal Trump they can do that. According to reports and the New York Times, the state of New York and the state of Georgia have both joined forces in opening a case against Trump. It appears in Georgia the reason (at least in part) for that case is none other than Trump ‘s phone calls to the state’s Sec of State.
The Times notes that the potential charges vary quite widely. Some of those charges include election interference, attempting to interfere with someone’s election duties (the Sec of State), and of course multiple in relation to his phone call to GA officials.
It’s yet another major turn of events for Trump who so far has largely avoided all prosecution for his crimes against the United States and beyond.