Will the GOP cave on gun control?
This is certainly a moment of political danger for gun owners -- followed shortly by intense, personal danger as ex-girlfriends, ex-wives, "triggered" liberals, and potential boyfriends of young daughters all call in to "red flag" anyone they think might own a gun and seems angry. But the fact is, so-called "red flag" laws won't change anything (at least not in a positive way) and are likely to instead make things dramatically worse.
Right now, we have laws against making violent threats, laws in many states enabling involuntary commitment of people who pose a danger to others, and most of those laws come with a prohibition on firearms ownership. They are already of questionable legality in some cases for lack of due process, they are already on the books, and they don't work. Every time this happens we hear about the warning signs, the calls to police, the threats. But no action is taken... and not for lack of legal authority. Sometimes the police don't bother. Sometimes they bother, but don't add the murdered to the NICS list. Sometimes the government sponsors straw purchasers smuggling guns to criminals (see Fast and Furious under Obama's watch).
Bottom line, background checks don't actually stop criminals from getting guns. Hardened criminals can get guns on the black market anyway. The people who commit mass shootings have usually come to the attention of law enforcement in myriad of ways before their mass murder but without being added to the appropriate lists or any serious action being taken. Adding red flag laws into the equation will do nothing but increase the false reporting rates and harass peaceful gun owners during divorces or even just a bad breakup with a girlfriend.
If Trump wants to win re-election in 2020, he absolutely cannot afford to piss off gun owners. He's going to have enough problems with the NRA sidelined, and he's already taken some actions that have pissed off the 2nd Amendment community. All we have to do is stay home, and he's a one-term president.
That said, other presidents -- both Bushes, for a recent example -- have danced around this issue successfully. They publicly supported assault weapons bans which Congress never sent to them to sign. At the moment, though, the Democrats control the House, and the Senate is in Republican hands by a very slim majority. The GOPe -- who hate Trump despite sharing his party -- might well send him a gun control bill hoping he would sign it and destroy his re-election chances. Without the NRA to speak up, Trump might not have the instincts to realize how bad an idea this would be.