Trump told reporters Tuesday that he will begin his first major paid media campaign, which he has refused to do despite large advertising buys from his Republican rivals and the super PACs supporting them, next month. Trump, who has no authorized outside group independently backing him, appears to be finally paying heed to polls that show the GOP race tightening in Iowa.

“When I see a 40, and I see a 12 or a 13 in second, I see no reason to spend,” Trump said of some recent national poll numbers on board his campaign plane. “But I feel I should spend. And honestly, I don’t want to take any chances.”

Trump told the media before his evening rally in Iowa that the $2 million a week would feature messages on border security, trade and protecting the nation from the threat of ISIS. The Republican front-runner said he had seen the first few commercials already.