A group of bipartisan senators have reached a gun safety framework, which includes enhanced background checks for those under 21, funding for mental health and school safety and state grants for "red flag" laws.

Why it matters: The deal falls short of what many Democrats want, but if passed, it would be the most significant gun safety measure in decades.

Between the lines: The core group of senators behind the deal, Chris Murphy (D-Conn.), John Cornyn (R-Texas), Kyrsten Sinema (D-Ariz.) and Thom Tillis (R-N.C.), are still working on writing legislative text, but are confident the deal will have the support of at least 60 senators — the threshold for legislation to pass in the chamber.

• Already, 10 Senate Republicans have signed on, including Sens. Cornyn, Tillis, Roy Blunt (R-Mo.), Richard Burr (R-N.C.), Bill Cassidy (R-La.), Susan Collins (R-Maine), Lindsey Graham (R-S.C.), Rob Portman (R-Ohio), Mitt Romney (R-Utah) and Pat Toomey (R-Pa.).
• 10 Senate Democrats also support the deal, including Sens. Murphy, Sinema, Richard Blumenthal (D-Conn.), Cory Booker (D-N.J.), Chris Coons (D-Del.), Martin Heinrich (D-N.M.), Mark Kelly (D-Ariz.), Angus King (I-Maine), Joe Manchin (D-W.Va.) and Debbie Stabenow (D-Mich.).
• Both President Biden and Senate Majority Leader Chuck Schumer (D-N.Y.) endorsed the deal.
• "Once the text of this agreement is finalized, I will put this bill on the floor as soon as possible so that the Senate can act quickly to advance gun-safety legislation," Schumer said on Sunday.

Between the lines: Translating this framework into text will be difficult, and the details will be crucial to the deal's success.

• "This IS an agreement on principles, not legislative text. The details will be critical for Republicans, particularly the firearms-related provisions. One or more of these principles could be dropped if text is not agreed to," a Republican aide involved in the negotiations tells Axios.

Details: The proposal includes an under 21 enhanced review process, which means buyers under 21 will be required to undergo an investigative period to review juvenile and mental health records, including checks with state databases and local law enforcement. The deal also:

• Clarifies the definition of a "federally licensed firearms dealer": Cracks down on criminals who illegally evade licensing requirements.
• Penalizes straw purchasing: Cracks down on criminals who illegally straw purchase and traffic guns.
• Supports state crisis intervention orders: Provides resources to states to create and administer laws that help ensure deadly weapons are kept out of the hands of individuals whom a court has determined to be a significant danger to themselves or others.
• Invests in children and family mental health services: Major investments to increase access to mental health and suicide prevention programs.
• Closes the “boyfriend loophole”— provides protections for victims of domestic violence: Convicted domestic violence abusers and individuals subject to domestic violence restraining orders will be included in the National Instant Criminal Background Check System.
• Funding for school-based mental health and supportive services: Invests in programs to expand mental health and supportive services in schools, including early identification and intervention programs and school-based mental health and wrap-around services.
• Funding for school safety resources: Invests in programs to help institute safety measures in and around primary and secondary schools, support school violence prevention efforts and provide training to school personnel and students.
• Invests in telehealth resources: Invests in programs that increase access to mental and behavioral health services for youth and families in crisis via telehealth.

What they're saying: “Families are scared, and it is our duty to come together and get something done that will help restore their sense of safety and security in their communities," the senators said in a joint statement.

• "We look forward to earning broad, bipartisan support and passing our commonsense proposal into law.”
• In a statement of support, Biden said: "Obviously, [the proposal] does not do everything that I think is needed, but it reflects important steps in the right direction. ... With bipartisan support, there are no excuses for delay, and no reason why it should not quickly move through the Senate and the House."

Senate Minority Leader Mitch McConnell (R-Ky.), meanwhile, welcomed the announcement but did not offer a direct endorsement:

• “I continue to hope their discussions yield a bipartisan product that makes significant headway on key issues like mental health and school safety, respects the Second Amendment, earns broad support in the Senate and makes a difference for our country,” he said.

Go deeper: House passes package of gun control bills

Editor's note: This story has been updated with additional details.