I've talked before about the rise of Hispanic voters. This is a major problem for the GOP. Yes, Hispanics tend to be conservative. So what? LOTS of Democrats are conservative (Obama for example). Hispanics tend to vote Democrat for a simple reason:
The GOP is not just conservative, it is ultra conservative - look at how few refused to sign the "Norquist No Tax Pledge" . They GOP is racist. It is not just against immigration - it proposes (and passes) anti-immigration laws that are over the top and unfairly punish people for being Hispanic, not just the illegal immigrations. It's easy to find Hispanics, it's a lot harder to find a french illegal immigrant.
As per the 2010 Consensus (Source), the following states have large Hispanic populations and GROWING
New Mexico is about 47%
Texas and California are both about 38%
Arizona about 30%Nevada about 26%
Florida is about 22%
Colorado about 20%
Of those, only New Mexico and California are already Democrat territory. The GOP can't really win there. Florida, Colorado, Arizona and Nevada are swing states. Texas is a Republican stronghold.
Even by 2016, some of those swing states, will turn Democrat. It will take a remarkably bad Democrat and a remarkably good Republican to win Nevada, Colorado, and Arizona. A good, Hispanic Democrat could theoretically take Texas. By 2020, Texas will be a Swing State.
The GOP knows this and they tried to gerrymander away the Hispanic vote in Texas. The case went all the way to the Supreme Court - where they got a slight victory (the court said the districts can't gerrymander away the Hispanic vote, but did reject the proposed lower court solution).
So the GOP is pretty screwed starting in 2016. UNLESS....
They put Marc Rubio as their Presidential candidate. With a blatantly Hispanic candidate, pushing conservative values that most Hispanics agree with, the GOP will be able to hold onto them.
Which is why Marc Rubio is the single most dangerous Republican in the United States today.
With him, the GOP can hold on to Texas definitely, and have a good shot at Florida, Arizona, Nevada and Colorado. Without him, they have no chance - assuming the Democrats don't put forth an idiot.
Truthfully, the only reason why the GOP hasn't already lost Texas is that many of the Hispanic population is illegal, and the rest have relatives that are illegal. They are scared to vote. But as time goes on, their children get born in the country and grow up as legal American citizens that are less and less afraid for their relatives.
Texas could very well be competitive for the Democrats in 2016.