My reading is that they mean to say the conservative party has continued to move so far to the right that conservative positions from only 15 years ago are now “radical lib” positions.
Though I hesitate to frame this as the Overton Window. In society at large, the Overton Window continues to move to the left, being gay is normalized now, cannabis is normalized now, I would frame the conservative movement as a desperate grasping to prevent the Overton Window from continuing on its current path, normalizing a genderless society for example.
Economically, both American parties are right wing corporate welfare state proponents.
The united states is a corporate plutocracy, you can buy power and influence, and being poor is being increasingly criminalized. While the system squeezes wealth from the middle class like a sponge. It is engineered to transfer your life savings into the hands of the healthcare owners at the end of your life, instead of to your children.