A top Republican senator is fact-checking President Donald Trump on the scope of the GOP’s forthcoming tax reform package.

Trump won’t be putting his name to the “largest” tax cut in United States history, Sen. Chuck Grassley (R-IA) tweeted Thursday, correcting the president’s now well-established political tag line on tax reform.

1/3 @reslDonaldTrump Ur tax cut will not be "largest in history of country" Here are the fact fr my own self Fact Checker — ChuckGrassley (@ChuckGrassley) October 12, 2017

Trump has repeatedly promised the “biggest tax cut ever” at rallies and on Twitter, without going into much detail on what that would entail. Most recently the president tweeted, “Republicans want the biggest tax cut in history.”

But Grassley had a reality check for the president:

2/3 when I chaired Finance 2001 $1.35T adjusted for inflation =2016 $1.865T in tax cuts 2003 350B=2016 $468B 2005 $70B=2016 $88B — ChuckGrassley (@ChuckGrassley) October 12, 2017

In other words, Grassley is pointing out that the tax cuts under former President George W. Bush, when adjusted for inflation, were much larger than anything Congress is currently debating.

In 2001, when Grassley chaired the Senate’s Finance Committee — which oversees tax reform legislation — Bush signed into law a $1.35 trillion tax cut. In 2016, that would be approximately a $1.85 trillion tax cut, Grassley noted.

Currently, Senate Republicans are suggesting massive tax cuts, but smaller than those passed under the Bush administration. The Senate’s budget proposal — which has yet to be voted on — allows for $1.5 trillion in tax cuts, a number that could shrink in the weeks ahead as Republicans try to reconcile what is looking like a major blow to the deficit.

Regardless, Grassley is still on board with tax reform. If Republicans manage to pass something resembling their tax reform framework, it would enact undoubtedly sweeping changes to the current tax code.

3/3 @realDonaldTrump regardless ur tax framework sets out badly needed cuts REFORM SIMPLIFICATION TO CREATE JOBS/ move byond ObamaSTAGNATION — ChuckGrassley (@ChuckGrassley) October 12, 2017

He just wanted to point out that they would not, however, be the “largest in history” — one of Trump’s favorite talking points.