Steve Forbes, chairman and editor-in-chief of Forbes Media, said on CNBC’s Squawk Box that Republicans need to move fast on a tax overhaul or risk losing the House in 2018.

Forbes said, “I think Trump realizes if this economy doesn’t grow, his presidency is finished, would be seen as a failure.”

He added, “That’s why I think he needs to move fast on the tax cuts, get things moving.”

Forbes unsuccessfully ran for president in 1996 and 2000 on a platform of overhauling the tax code.

Forbes commended Trump on his executive actions to reduce the burden of Obamacare, and rescind Dodd-Frank regulations but he says it’s time to enact real reform. He insists, “Trump has got to deliver the big stuff.”

Forbes says that tax reform would create growth, but wants a “straight vanilla cut.” He continued, “We’ve done that before. It works.”

Forbes hopes for a tax overhaul, but worries about including a border adjustment tax.

The former presidential candidate says that the border tax is “insane.” He added, “Economically it’s wrong. Politically it’s wrong.”

Forbes says that the onus is on President Trump and Congress to produce results from tax reform.