Most commentators argue that the current stand off over the government funding - the debt ceiling - and the ACA - etc..., all stem from the demands imposed by a very disciplined and cohesive Tea Party Caucus within Congress. It contains 50 or so members - but has been able to drive its agenda forcefully.
For more info
- Wikipedia - Tea Party Caucus.
- Politico - The Tea Party Returns.
- Who is the Tea Party in the House?
- NYT- The Tea Party Caucus
The Hill argues that the caucus has gained control over Speaker Boehner - which allows it to control the House to a great degree.
By the way, what is a congressional caucus?
Here is a comprehensive list of caucuses in Congress.
