Earlier Tuesday, Trump said that his proposed plans, like the infrastructure bill, will pay for themselves by pushing national gross domestic product (GDP) growth to 3 percent. This, the president says, will increase tax revenue.
"Growth, no doubt, would help the nation's finances on a whole bunch of fronts," said Pawlenty, a Republican who previously sought the party's nomination for president in 2012.
While Trump's plan works in theory, Pawlenty said what conservatives have to ask themselves is: "how much are you willing to bet ahead of time that it's actually going to happen at a risk of fueling more deficits and more debt."
"If [Republicans] make [the debt] worse, because they misfired on growth assumptions, that's not going to end well for conservatives," Pawlenty said.
Ahead of Trump's address to a joint session of Congress, Pawlenty said it's time for a more detailed plan to be presented.
"And by the way, it's getting later than you think," Pawlenty said. "It doesn't all need to be done in the first 100 days, but, given the nature of presidencies and their first year, if you don't have things rolling by summer… they do need to get moving."