Some Texans seem to have the idea that their Republican Southern Strategy hold on state politics may disappear in the near future because of increasing numbers of immigrants (particularly Hispanic) and more poor people who tend to vote for Democrats, and fewers elderly white rural Republican voters as old folks die and more country folk move to cities and suburbs. So follow me into a possible future after Texas declares its independence (below the fold).
In the 2012 presidential election Texas went 57% for Romney, a majority of about 1.25 million voters, so losing some Republicans and adding some Democrats won't take long to reverse this. Texas entered the Union as the Republic of Texas and could return to this condition if a majority of voters concur and the federal government allows it. I can't see US troops invading Texas to enforce the solidarity of the Union, so let's suppose they get away with it.
As a nation separate from the US they may well have high import and export duties and tariffs put on them for US goods such as cigarettes, US national brands of beer and liquor, clothing, cars, and luxury items. Their oil may be difficult to sell and likely would require fees to move across the border.
New Orleans and possibly Mobile would experience a boost in commerce from smuggling, the cities reviving with a host of antrepreneurs, local boaters and pilots, brokers (read: crooks) and a lot of untaxed money flowing into the financial market.
I don't believe this would reverse the population trends toward more Hispanic and below poverty voters, even with the expected Draconian immigration laws. In a few years there will be at least a plurality of Hispanic voters. How likely are they to vote to petition the United States of Mexico for admission? This will reverse the actions of the Texas Rebellion of the 1840s and potentially pave the way for repatriation of more teerritories lost to the gringos.
Again, I don't think the USA would go to war with Mexico over this cause. It will have interesting effects on sports, however. In baseball, the Texas Guardabosques would play in the American League West, just as the Toronto Blue Jays play in the AL East. In American football, the Dallas Vaqueros and Houston Tejanos would potentially be powerhouses, while in the NABA (North American Basketball Association) the Houston Cohetes, San Antonio Estimulars, and Dallas Disidentes may play for the championship. The first hockey team in Mexico, the Dallas Estrellas, would have the support of the entire country. Only the Houston Astros would retain their name. Of course, soccer (futbol) would be the primary sport in Mexican Texas including all the high schools now worshiping at the altar of American football.
In addition, this would practically guarantee Democrat victories in national elections with the electorate in New York and California solidly in our camp.