[Alberta's Child]

If he can’t make a promise for Congress, then why did he make, on numerous occasions, promises for Congress?

Because he was a political candidate running for office, and political candidates promise the voters whatever he thinks they want.

Here's how a very brief conversation between the President and Congress might go:

Trump: "We have to fund the border wall because that's what I promised during my campaign."

Congress: "WE didn't promise that to anyone. If you want a border wall, go build it yourself and call it the Great Wall of Trump."

[joesbucks]

One of the biggest complaints from the electorate is candidates don't deliver on their promises. It's one reason Trump was elected. He said he would deliver on his campaign promises.

As to the border wall, he said Mexico was going to pay for it. Other than maybe approving it, he really shouldn't have to go to congress for anything else.