Today (December 29th) is the 167th anniversary of Texas' admission to the US as the 28th state. We generally don't make a big deal about it. We prefer to celebrate Texas' independence on April 21st - San Jacinto Day - when the forces of Santa Anna were defeated near what is now the mouth of the Houston Ship Channel. We don't even make that big a deal of the day the Texas Declaration of Independence was signed, March 2. That's curious since the US celebrates its independence when its declaration was signed - not when the battle of Yorktown was concluded.
I have no idea why that's the case, but given Texas' identity, its little surprise we make a bigger deal about independence from Mexico than admittance to the US because, to be honest, the state lost independence when it was annexed. It became solvent, but .... you know ...
One little detail we tend to forget is that Mexico still did not recognize Texas independence at all, so there were legal disputes about what in fact was going on in 1845. Was the US annexing an independent sovereign state or taking over control of the state of an adjoining nation? Despite the lines we see drawn in maps today - much of the territory was in fact no man's land - and no one had yet to tell the Plains Indians that they did not control the land. This would wait until the 1870s.
That Mexican-American War ultimately settled the issue as far as Mexico was concerned - along with what would become the American southwest. Wars tend to settle what politics cannot. This helps explain the strained relationship we've had with Mexico over much of our history. Canada too - we made a brief attempt to take it over during the war of 1812. They still have hard feeling about that too.
