Yes, sudo or polkit will always ask for the user password. Root has its own account and have full access on everything.
This asks for the root password:
su && whoami && exit
This asks for the user password:
sudo su && whoami && exit
(but only if the user is in the wheel group)
This way you have only temporary root access for only one task and not the whole time. And distinction between the real root and fakeroot (sudo), ensure more security.