Senate Democrats estimate the wall that President Donald Trump has promised to construct along the southern border could cost $66.9 billion, according to a new report released Tuesday afternoon.

The price tab projected by Trump’s opponents far exceeds previous estimates, which topped out at $21.6 billion. The Democrats’ report is based on extrapolations, not hard data. It says that although the Department of Homeland Security and Customs and Border Patrol have not provided a “reliable cost estimate” for President Trump’s signature campaign promise, the party has reached its projections using information provided by CBP officials, including the Trump administration’s 2017 budget request and 2018 budget proposal.

The Trump administration has redirected $20 million to begin the construction of border wall prototypes in San Diego and start the planning process to erect barriers in parts of Texas. But that sum is only the beginning. In Trump’s budget proposals, funding for the wall jumps to $999 million in the 2017 supplemental request and $2.6 billion in the 2018 blueprint. From…