NOTE: This primer has been updated as of March 2019.

During yesterday’s Oval Office meeting, House Democratic Leader Rep. Nancy Pelosi (D-CA) said this about border security: “We have to have an evidence-based conversation about what does work, what money has been spent and how effective it is.”

TCS has got you covered. At least on how much has been spent. TCS went through budget documents and tallied up all the border spending since FY2007. $12.2 billion. Here’s a primer on border barrier spending and we even tabulated the share of the cost borne by each state.