Obamacare isn't dependent on the financial markets. The reputation of the Repugs will be shattered by a shutdown. I am thrilled the tea baggers and libertarians are ripping apart the Repugs. A HUGE win for USA.
For the US default threat/debt ceiling extortion, it's total bull threat because the 1% (bond holders), Wall St, the entire financial sector, aka, Congress' paymasters, will simply not let the Repugs do it.
Dems shouldn't not give in to any extortion by the anarchists tea baggers, no compromises, because they hold the Senate and WH, which is why the House extremist minority is trying extortion since they don't have the power otherwise.