CHICAGO (CBS) — Congressman Adam Kinzinger might still have some doubts about Republican nominee Donald Trump, but he brought a message of party unity to Illinois delegates at the Republican National Convention.

Kinzinger, a Republican from Channahon, said he’s had concerns about Trump when it comes to foreign policy, but he told Illinois GOP delegates they all need to work together.

“Some of you know I was chief among my concerns for our current frontrunner, but we have to stand together as a party united. We have to win the White House. We have to hold the Supreme Court. We have to remember our mission. We have to hold the House of Representatives,” he said.

Kinzinger has previously said Trump doesn’t know what he is talking about on foreign policy matters, and has expressed serious reservations about supporting Trump as the Republican nominee.

“Donald Trump, if he becomes our nominee, God forbid, and if he becomes president, really needs to surround himself with people that actually understand how the world works, and actually understand foreign policy,” he told CNN in February.

“I don’t think he’s going to be the nominee, but if he does, I’d have a long, hard decision to make, personally. ‘dI put my country above my party any day,” he added.

The congressman, who has not formally endorsed Trump, told reporters at the convention what could seal the deal.

“I want to see how the speech goes tomorrow. You know, this is the opportunity for the Republicans to unite. It’s our week to unite. The point I made is extremely important. Another four years of Barack Obama through Hillary Clinton, I think, on foreign policy would be detrimental,” he said. “Lastly, we have to hold the House, we have to hold the Senate, and this country needs something different.”

A common theme at the convention has been the November election is a binary choice, and Republicans won’t vote for Hillary Clinton.