Republicans in Congress want to delay their approval for President Donald Trump's request to build a Mexican border wall. According to Reuters, costs are already climbing to well over $1.5 billion, with an expected completion cost of $21.6 billion.

During his run for president, Donald Trump promised to build a huge wall that would prevent Undocumented Mexicans from entering the U.S. illegally. He insisted that it would be paid for by Mexico. The Mexican government has said repeatedly that it has no intention of paying for the wall – now or ever.

Who should pay for the wall?

This begs the question: who will pay the $1.5 billion to build the wall? Democrats are saying Trumps' Mexican border wall is terribly planned and there is no need to build yet another wall costing billions of U.S. taxpayer dollars when there are border security measures already in place. The $1.5 billion would take much-needed funds from programs that many American people can't live without. Democrats warn they will block a spending bill if money for the border wall is included in the 2017 fiscal year.

Trump's campaign promise to construct a giant wall is also meeting with resistance from his own party. Republicans representing border towns say the federal government would need to buy land in many of the bordering location just to build the edifice – causing construction costs to skyrocket.

Republican party leaders say their bill will more easily be accepted without extra military spending and exorbitant border construction costs, adding those programs will be considered at a later time.

Super-majority vote needed

According to Reuters, Trump's wall could end up costing $21.6 billion by completion – far more than the President's $12 billion estimates.

Given the super-majority vote needed in the Senate, Republicans are skeptical about Congress' ability to approve the necessary funds needed for construction.

Roy Blunt, a Republican Senator stated on Tuesday that the spending bill must pass by April 28 in order to prevent federal agencies from shutting down, as their funds expire on that date.