What is the idiom for the line Whose stern impassioned stress A thoroughfare for freedom beat in America the Beautiful mean?

The idiom "A thoroughfare for freedom" in the line "Whose stern impassioned stress A thoroughfare for freedom beat" from "America the Beautiful" means a pathway or route that facilitates the advancement and promotion of freedom. It suggests that the ideals and principles of freedom are actively and forcefully being promoted and upheld. The Word "thoroughfare" typically refers to a main road or route for travel, so in this context, it symbolizes the journey towards freedom and the efforts made to maintain it.