Source? The constitution, I guess, along with the rules governing the operation of each branch. Even when they are in session, Congressmen either show up, or not. That's the way Congress works. What you posted says he can call a special session. That's it. There's no mention of use of force or of being able to require (under threat of what?) that they all show up, and then having an armed man make sure they are unable to leave until they've done what the president dictates. All is says is that he can call a special session. And all a special session is is a convening of Congress outside their normal schedule. All the usual rules apply, and the usual rules don't require everyone to attend. Surely you are aware that congressmen often miss votes and other sessions, yes? Yet you posted that Article 2 bit as proof he could lock them up and make them play nice, when it says nothing of the sort.
And yes, if 51 senators show up, they can conduct business. I never said anything to the contrary. Actually, if only 2 senators showed up, they could technically conduct business as long as no one made a quorum call, I guess. But that has fuck all to do with what you said, which was that there was some mechanism for the president to force Congress' hand.
Honestly, I have no idea what you are arguing about. You asserted that, based on what you posted, the president could confine Congress to their offices and forcibly keep them there until they pass a budget. He can't. That's what my post was explaining. He can call a session, but he can't force participation, or anything else. He can't lock them up until they do their jobs, and nice as that might be right now. I don't find it "appalling" that the president would try to get Congress to do his job. I never said anything remotely suggesting I might be. I simply said that there is no way for him to lock them in their offices and keep them there until they do their job. It's not appalling; it's just not possible as he does not have the authority to do that.
You said he can do something, and posted as proof something that says nothing of the sort. Then I pointed that out, and now you are making it into some political thing where I am appalled the the president might take a firm hand with Congress. Huh?