House Democrats may pass a new $600 million border security bill Tuesday and send it to the Senate because of constitutional concerns with a measure passed by the Senate shortly before the August recess, according to a House Democratic leadership aide.

That would delay disbursement of the money contained in the bill until the Senate returns in mid-September — unless Senate leaders decide to return early to pass it.

The Constitution requires revenue measures to originate in the House. Sen. Charles Schumer’s (D-N.Y.) border security measure, which would add 1,500 border guards and equipment, was introduced just hours before it was attached as an amendment to a House appropriations bill and passed by unanimous consent.

But the Senate messed up, according to the House aide, by attaching a revenue hike to an appropriations bill instead of using a House-passed tax measure. Schumer’s bill is paid for largely with a higher fee on work visas.

The Obama administration has urged the House to clear the Senate-passed bill and send it to the president’s desk. The House’s initial bill passed by voice vote last month.