I assume u mean the French Revolution? the 1st Estate was the clergy / religious folk. they didn't have to pay the annual tax.
2nd Estate was the nobles
3rd Estate was the peasants and pretty much everyone else not a noble or a clergy.
a group of boyz and a band
The primary issue that divided the country as the US expanded its borders was that of slavery--with the pro-slavery population wanting the new states to be slave and the abolitionists wanting it to be free. The fact that it was eventually decided that the issue of slavery would be decided by "popular sovereignty" eventually led to the Civil War. <span />