Can someone explain how our spending / legislature works in basic terms?

Basically, I am curious about the interplay between the House, Senate, and President (I imagine there are more, though). I don’t need a huge amount of detail, just enough basics to understand the gist.

And I am curious about how spending works. As far as I understand it, Congress dictates what to allow spending on.

However, I am curious why there’s all this “Obama is a huge spender” nonsense floating around. Doesn’t everything have to go through Congress? How does spending work? Is it approved even if tax revenue isn’t there to support it? Is this why spending had no shock when the recession hit (but tax revenues did)?

How do new bills get passed, too? Does someone propose something and then get voted on in both houses/approved by the President? What is required? What does it mean when “Republicans control Congress” – does that just mean there are more Republicans than Democrats seated?

Apologies if this question is framed in a funny way but I am just trying to understand.

Both the Senate and the House have endless committees and subcommittees. Legislation originates in these. Typically a subcommittee writes the legislation, then it goes to the full committee for an approval vote. If the committee approves it, then it actually goes to the full House or Senate. Often you’ll see two similar but not quite identical pieces of legislation passed in the Senate and the House. When that happens, they need to negotiate to eliminate the differences and produce a final piece of legislation that can be approved by both. Then the bill goes to the President for signing. If the President vetoes, then either house of Congress can try to override the veto with a two thirds majority.

(Of course this ignores filibusters, earmarks, anonymous holds, and so forth. It’s complicated.)

When the Republicans control the House, that means they can appoint a majority of Republicans to every House committee; likewise for the Democrats in the Senate. Hence if everyone voted party line in committees, they could make sure that only legislation approved by the majority party ever gets voted on by the full House or Senate.

It is true that President Obama has no actual power over what Congress passes other than the power to veto. In practice, though, the President usually makes the decisions for the major legislation put forward by his party in Congress.

If all that’s too complicated, here’s a shortened version.