President Donald Trump plans to propose Wednesday what his administration has billed as the largest tax cut in the country’s history in hopes of spurring economic growth.

The plan calls for 15% tax rates on all businesses, deeper than the rate cuts proposed by House Republicans. Those rates are likely to drive Democratic opposition and spark complications in Congress because changes in tax policy that the Senate can pass on a party-line vote, under the budget procedure known as reconciliation, aren’t allowed to create long-run budget deficits.

Treasury Secretary Steven Mnuchin said Wednesday morning that the administration wants permanent policy changes, but that temporary cuts could be considered, too.

“This is going to be the biggest tax cut and the largest tax reform in the history of our country,” he said at a conference in Washington sponsored by The Hill newspaper.