on a patriotic mood

God shed His grace on thee. What are you saying when you say that? If you're quoting the song "America the Beautiful," then you're not saying that God did shed His grace on America. Nope: you're praying that God will shed His grace on America. That phrase is in the subjunctive mood.

The fact that "shed" [subjunctive] is the same as "shed" [indicative] can be confusing. So confusing that many people mistakenly go on to the next line to sing ...and crowned Thy good with brotherhood. But that's not how it goes. It's "crown," not "crowned." So, the whole statement is

America! America! God shed His grace on thee,
And crown thy good with brotherhood
From sea to shining sea.

Interesting, right? The key there is really the "crown," which has to be subjunctive. Like many such statements — "God bless you," "Peace be with you" — the telltale may is missing. It's understood: "May God bless you," "May peace be with you." Except that may has been missing for so long we sometimes don't even hear it.

"Goodbye" is subjunctive, then. It's a shortened way to say "God be with ye," which is a shortened way to say "May God be with ye."

The may does show up in later verses, though, just to reassure us: May God thy gold refine.

My July 4th wish? May we always remember that that line is subjunctive.