Good For The Roses

"16Then it will come about that any who are left of all the nations that went against Jerusalem will go up from year to year to worship the King, the LORD of hosts, and to celebrate the Feast of Booths. 17And it will be that whichever of the families of the earth does not go up to Jerusalem to worship the King, the LORD of hosts, there will be no rain on them. 18If the family of Egypt does not go up or enter, then no rain will fall on them; it will be the plague with which the LORD smites the nations who do not go up to celebrate the Feast of Booths. 19This will be the punishment of Egypt, and the punishment of all the nations who do not go up to celebrate the Feast of Booths." Zechariah 14:16-19

This prophesy has been on my mind lately. To get the full intent of these verses, it would be helpful to read all of Zechariah chapter 14-in simple, the Lord brings all of the nations of the world together against Jerusalem in order to judge and conquer them, setting up His Millennial Kingdom. Psalm 2 is a great companion scripture to Zechariah 14.
"any who are left of all the nations"-after that Day when Christ returns, the world population will be decimated. Look to the book of Revelation, with God's judgments/plagues coming down on a world which had refused His offer of Salvation. Decimated populations is inadequate language, but it will do for now.
There will be a remnant of humanity, the 'any who are left', and those peoples will be called to go up to Jerusalem and worship the King. As these verses state, some will be unwilling. No surprise.

Doug's speculation, meaning my opinion, which could be wrong as wrong can be:
I think that the individual peoples will decide what they will do; I am going to use myself and my buddy Bill Maher as examples.
Let's say that Bill and I each own part of a duplex in Lithuania when Christ returns-for the sake of this speculation, I wasn't "raptured" but instead lived through the Tribulation period.
Christ is on His throne in Jerusalem, and the edict goes out for all the nations to go up to Jerusalem to worship God in the Feast of Booths.
Egypt has declared that they will not go up, even though they know that they will be plagued with no rain, no favor from God, have no part in the common Grace.
Lithuanians gladly go up to Jerusalem, myself included, but Bill, who hates Jesus Christ, moves to Egypt, because he would rather die in the desert than worship Christ.
Populations will shift like this all around the world-those who would worship God that live in Egypt will move to a nation that will go up; those who refuse to worship will find their way to Graceless nations.
Right now I am an American, and I serve God in America. If America were on that Graceless nations list, I would move to Lithuania (example) because as much as I love my country, I love God more, and I wouldn't stay in a place that God would curse.
Merely speculating, but I think that is how it will go. Zechariah is a prophetic book filled with mind-blowing truths. May God Bless your reading of it.