It clearly says in Deuteronomy 24:5 that newly married men are not allowed in the army, and must stay home and enjoy their wives for the first year of marriage, doesn't it?

Or are we free to only obey those biblical principles which suit us?

America isn't a Christian nation, it has a secular government. It's not their responsibility to see how long a man has been married. Besides, why would America have to enforce old Jewish law?

Assuming a person or entity is following Judeo-Christian law, what determines which rules in the Bible are followed, and which ones are cast off as "old Jewish law"?

A Christian must abide by the New Covenant, not by the Old Covenant which was made for the Jewish people.

Why were "old Jewish laws" left out of New Testament teachings, anyway?

Different strokes for different folks. When Jesus brought the New Covenant, some of the old rules didn't apply anymore.

Why didn't they apply anymore?

Jesus Christ, mipadi. The answer is Jesus Christ.

Christ's passion and resurrection fulfilled the Old Covenant and brought forth the New Covenant.

I know Jews go by the Old Covenant, but I didnt know Christians only go by the New, and not the Old.

Why is that? I mean, why would laws change?

Don’t forget that America is democratic and republic.

Christians go by both. Here's an article that explains the old testament:

http://www.newadvent.org/cathen/14526a.htm

Christians go by both if it wasnt the Holy Bible wouldnt have the old and the new testiment implanted by them

Oh okay, thanks. Thats what I thought... I was just getting confused over other posts.

American grew up on christianity thats why on the dollars bills it says "In God We Trust" but now that America has developed they learned not to mix religion with government.