AUSTIN, Tex. — More than 100,000 people who signed an online petition calling on the Obama administration to allow Texas to secede from the United States and create an independent government received an official 476-word response from the White House last week.

The short answer was no.

But the response — in which a White House official said the founding fathers established the United States as a “perpetual union” — hardly discouraged the Texas secession movement, which has been simmering for decades but gained momentum after the re-election of President Obama.

On the opening day of the Legislature here last Tuesday, supporters of the Texas Nationalist Movement — a group that wants Texas to sever its federal ties and become an independent nation — met with Republican leaders, including Lt. Gov. David Dewhurst. It was another sign that ideas once regarded as radical and even unpatriotic have found a measure of support, or at least sympathy, among some conservatives.

The movement also scored a mention in one legislator’s opening-day speech, though it was not a reference that pleased supporters of the cause. “Our economy is so vast and diverse that if Texas were its own country — and no, don’t worry, that isn’t something we’re going to do this session — but if we were, we’d be the 14th-largest economy in the world,” the speaker of the House, Joe Straus III, a San Antonio Republican, told lawmakers.