If the wall is a matter of National Security does Trump need the approval of Congress to build it?

No, he doesn't. He could have the Army Corps of Engineers and Navy Seabees building it.

The $ would come out of the War Dep't budget. (they lose track of Billions every year....they wouldn't miss it)

Not really.

Congress controls funding.

Most people know that.

Even items involving national security, funding needs approval by Congress.

Actually Congress first approved it during the 2006 lame duck Congress. Republicans had just lost the House and the vote was along party lines!

Anything using federal money requires an EIS (environmental impact statement) before any construction can start. The EIS has yet to be written. By the time a thorough study is completed, Trump will be out of office.

Yes, if he wants to spend billions of taxpayer dollars he needs Congressional approval.

No but he needs Congress to approve the money for it.

The Democrats want border security too, but think there is a better way than this wall that will employ many of Trumps friends in building it.

But we agree with Mexico paying for the wall but not the US Taxpayers.

No, why would he?

As an FYI Congress has already approved the building of the wall... now it just needs to be funded

He doesn't need congress to approve the wall. He needs congress to approve the budget.