It is a tale of two Texans, with two divergent responses to the mass shooting that killed 19 children and two teachers in their state this week.

Senator Ted Cruz has angrily dismissed any talk about gun safety measures and doggedly insisted he will speak to the National Rifle Association’s annual meeting in Houston on Friday. Senator John Cornyn has backed out of his speech and pledged to try to find some compromise with Democrats on new gun laws.

The N.R.A.’s convention opens under the shadow of two mass shootings perpetrated by gunmen carrying military-style assault rifles — the first in Buffalo, N.Y., the next in Uvalde, Texas, 303 miles from where the group is gathering.

One after another, Mr. Cornyn, Texas Governor Greg Abbott, and Representative Dan Crenshaw, all Republicans, have discovered scheduling conflicts that have made their planned, in-person speeches infeasible. Not Mr. Cruz.

“I’m going to be there, because what Democrats and the press try to do in the wake of every mass shooting is they try to demonize law-abiding gun owners, try to demonize the N.R.A.,” Mr. Cruz told a CBS reporter ahead of the speech, planned for Friday afternoon.

He also counseled that schools should respond to the Uvalde slaughter by ensuring they have only one door to enter and exit, with an armed guard monitoring it.

Mr. Cornyn canceled his speech — his office said he had done so before the Uvalde massacre, after discovering a scheduling conflict — and declared on the Senate floor, “I’m not interested in making a political statement. I’m not interested in the same old tired talking points. I’m actually interested in what we can do to make the terrible events that occurred in Uvalde less likely in the future.”

Senator Mitch McConnell, Republican of Kentucky and the minority leader, has tasked Mr. Cornyn, a close ally, to keep tabs on high-stakes bipartisan talks on gun legislation that can win at least 60 Senate votes to break through a filibuster.

Should such a deal materialize, the filibuster is likely to be led by his fellow Texas Republican, Mr. Cruz.