Impeachment is an empty gestor. It's removal that would lead to a Second Civil War. The only way that happens is if a large segment of Senate Republicans turned against President Trump during an impeachment trial.
If President Trump was removed, the Democrats would gun for President Pence. If successful, they would install Nutty Nancy as Acting President.
congress misreads us out here all the time.
If they thought they (GOP) could join in the impeachment of Trump and not pay a price, they would.