The Senate's long-awaited national security deal landed with a thud Sunday evening as House Republicans vowed to block it from a vote and at least one Senate conservative demanded a change in leadership.

Why it matters: The deal took months of agonizing negotiations. Within the first few hours of the bill’s grand reveal — Republicans across the spectrum are driving the nail in the coffin.

• The bill has been pronounced dead on arrival in the House, which will make its passage even tougher in the Senate.
• “Only a fool, or a Radical Left Democrat, would vote for this horrendous Border Bill,” former President Trump posted on Truth Social on Monday.

What they're saying: "I've seen enough. This bill is even worse than we expected," Speaker Mike Johnson (R-La.) said in a statement. "If this bill reaches the House, it will be dead on arrival."

• House Majority Leader Steve Scalise (R-La.) swore the bill "will NOT receive a vote in the House."
• House GOP conference chair Elise Stefanik (R-N.Y.) called the deal an "absolute non-starter."

Zoom in: It's not just the House. Some conservatives in the Senate pounced.

• “I'm a no,” posted National Republican Senatorial Committee chair Sen. Steve Daines (R-Mont.) Monday morning. Daines was the first member of GOP Senate leadership to come out in opposition.
• "I cannot understand how any Republican would think this was a good idea—or anything other than an unmitigated disaster. WE NEED NEW LEADERSHIP — NOW," Sen. Mike Lee (R-Utah) posted on X. He called for Republicans to filibuster the package.
• "I cannot imagine why any Republican supports this atrocious proposal," Sen. J.D. Vance (R-Ohio) posted.

The big picture: The House and Senate will be moving in opposite directions this week as the House votes on a standalone $17.6 billion Israel aid package.

• House members in both parties have expressed qualms about undermining the Senate deal — and specifically Ukraine funding —with GOP hardliners criticizing its lack of pay-fors and border provisions.
• Still, the Israel-only bill stands a chance of passing the House with even more than the 12 Democrats who voted for the GOP's last attempt at an Israel aid bill in November.

What we're watching: If the Senate manages to pass the sweeping national security package and the House passes the Israel-only bill, they could head to what is called a conference committee in an attempt to reconcile the differences, one House Republican told Axios.

Editor's note: This article was updated Monday with new comments from Trump and Daines.