What is aid meant to do?

Here is a call for a comprehensive review of the foreign aid delivered by the US, framed by the author as a way to regain wide buy-in for foreign aid from Republicans.  I think the last paragraph is the most relevant, for the US or any country, to be clear on what they are trying to achieve through their aid.

"Finally, a review should include a conversation about the basis on which the United States sets its priorities for allocating aid — whether it is determined by need, merit, national security, the potential return on investment, or other reasons. There is no single right answer, nor are the many justifications for aid spending necessarily discrete. But understating the values that are the basis of U.S. aid would help us better understand what America’s goals should be, and what it expects aid to accomplish. The answers could provide some surprises in terms of finding common ground, and would provide a much clearer explanation to a skeptical public about the importance of global development."