In Iowa this afternoon, Sen. Marco Rubio was introduced at a rally by his Senate colleague Joni Ernst of Iowa. As she took the stage, Ernst repeated her promise not to endorse anyone before the Iowa caucuses, but explained why she chose to rally with Rubio.

“I have said, I’m not going to endorse in this race, and that is a promise that I am going to keep to Iowa,” she said. “So I’m not endorsing, but I do want to introduce and welcome as many folks to the State of Iowa as possible.”

But Ernst spoke warmly of her colleague, remarking that Rubio was “near and dear to my heart” and “a good friend to me” in the Senate. While Ernst signaled a willingness to rally with other Republican candidates, Rubio is the only one she has rallied with in Iowa so far.

Rubio invested a great deal of time and effort in Earnt’s 2014 Senate race, endorsing her early in the crowded Iowa Republican primary, and he campaigned frequently for her in the state. Rubio also spent $243,729 on Ernst’s race from his political action committee to help her be competitive in her primary.

This afternoon, Ernst praised Rubio for his strong record on national security and touted her experience working with him on those issues.

“He knows what it is to keep our country safe from the threats that are out there,” she said, praising Rubio for understanding the global threats “very well” and having “the confidence necessary in a leader.”

“I know that he wants to work hard to make sure that [the] American dream is alive for our children,” he said. “I’ve seen him fight that for his children, for my children and for your children as well.”

Ernst won in Iowa campaigning as a mother, veteran, and conservative who was strong on national security. Without an endorsement, Rubio’s team appeared content, at least, to have Ernst onstage with Rubio in Iowa. During the speech it became immediately clear why.

After the introduction, Rubio explained that just like Ernst, he decided to run for office even though the Republican establishment tried to tell him it wasn’t his turn yet.

“We both come from humble beginnings,” he said, retelling Earnt’s story of how as a little girl, she often wore bread bags on her shoes in bad weather to keep them from wearing out faster.

“I lived paycheck to paycheck, I grew up paycheck to paycheck,” he said, reminding the audience that “so did Joni Ernst.”

Rubio also talked about how if he was elected, he would end “ridiculous” EPA regulations–reminding Iowans that Ernst was a “leader” in fighting against them. And he talked about what he would do on national security, reminding voters that it was an issue that “Joni cares about deeply.”

“Joni’s right,” he said, announcing why the United States had to “destroy ISIS.” After talking about fixing the Department of Veterans Affairs, Rubio reminded supporters that the issue was “near and dear to Joni Ernst’s heart.”

By teaming up with Ernst, Rubio sent the message that he was part of the new generation of conservative Republicans who were not only strong on national security, but also promoting a modern message for the party.