This weird part of the Tonkin Gulf Resolution references the long-forgotten 1994 children's comedy Blank Check starring former Family Ties actor Brian Bonsall.

Oh, wait. That's not what's going on in the Tonkin Gulf Resolution at all.

Although writing checks is quickly becoming obsolete, the symbolic concept of a blank check is still relevant. It basically means being handed unlimited money. Yum.

When Congress says "the Congress approves and supports the determination of the President, as Commander in Chief, to take all necessary measures to repel any armed attack […]" (5), or "the United States is, therefore, prepared, as the President determines, to take all necessary steps, including the use of armed force […]" (6), the blank check idea is being implied. Essentially, Congress is giving the President unlimited authority, resources, and power to carry out the mission of bringing peace to Southeast Asia.

…which is way less family-friendly than Brian Bonsall buying a castle for the low, low price of $300,000.