Florida Sen. Marco Rubio (R) has endorsed former President Donald Trump for 2024 on the eve of the Iowa caucuses, citing Trump's positive impact on his activities in the Senate. 

"When Trump was in WH I achieved major policies I had worked on for years," Rubio posted on X.

When Trump was in WH I achieved major policies I had worked on for years (like expanded Child Tax Credit & tough sanctions on regime in Cuba & Venezuela) because we had a President who didn’t cave to special interests or let bureaucrats block us.

I support Trump because that…

— Marco Rubio (@marcorubio) January 14, 2024

"I support Trump because that kind of leadership is the ONLY way we will get the extraordinary actions needed to fix the disaster Biden has created," he added."It’s time to get on with the work of beating Biden & saving America!"

More endorsements

Florida's other senator, Rick Scott (R), has also endorsed Trump.

On the same day, Gov. Doug Burgum (R-ND) gave his endorsement of Trump, becoming the first 2024 GOP primary candidate to do so.

Trump currently leads polling in Iowa with 48% support. Other candidates include former South Carolina Governor Nikki Haley (20%), Florida Governor Ron DeSantis (16%), and billionaire Vivek Ramaswamy (8%).

DeSantis said he would not drop out of the race even if he places third in Iowa, and has plans for events in New Hampshire and South Carolina after the caucuses on Monday.

Foregone conclusion

It does appear that the primary will go to Trump. He's ahead in every state's polling by double digits.

Still, anything could happen, and DeSantis is probably wise not to give up prematurely.

To this point, however, Trump has endured four criminal indictments and has gained in the polls with each one.

This is on top of several civil suits, including one that alleged he raped a woman and one that could cost him $370 million and the ability to run his own company.

Bulletproof?

If Trump isn't bulletproof as a Republican candidate at this point, it's hard to imagine what could take him down.

Whether that will translate to the general election is another question that we may not be able to answer until it happens.