Senator McCain has argued forcefully for intervention in Iraq, in response to events outlined by Jim. It is conceivable that surgical strikes might tip the balance and restore stability to Iraq. But hope is not a basis for policy (or shouldn’t be).
The Senator has in the past opined on the Iraq issue. Regarding the challenges of a conflict in Iraq, this quote from 2002:
…I am very certain that this military engagement will not be very difficult. It may entail the risk of American lives and treasure, but Saddam Hussein is vastly weaker than he was in 1991. He does not have the support of his people.
Regarding at least part of the casus belli, this 2003 statement FoxNews:
I remain confident that we will find weapons of mass destruction in Iraq.
This his view today The Hill:
“There is a need for immediate action,” McCain said on the Senate floor. “The worst option is to do nothing.” … McCain said political reconciliation between Islamic groups in Iraq is key to peace, but said that can’t be a “prerequisite for military action.”
McCain called for U.S. airstrikes in the region, if for nothing else than boosting morale.
At this juncture, it might be useful to recall what budgetary costs we have already incurred in Iraq (from this post).
Figure 1: Cumulative direct costs, in current dollars by fiscal year, in the Iraq theater of operations (“Operation Iraqi Freedom”). Does not include resulting debt service. Source: Amy Belasco, “The Cost of Iraq, Afghanistan, and Other Global War on Terror Operations Since 9/11,” RL33110, Congressional Research Service, March 29, 2011, Table 3. Data for FY2011 is for continuing resolution, for 2012 is Administration FY2012 request.
Figure 2: Cumulative real direct costs, in constant (FY2010) dollars by fiscal year, in the Iraq theater of operations (“Operation Iraqi Freedom”). Does not include debt service costs. Source: Nominal figures from Amy Belasco, “The Cost of Iraq, Afghanistan, and Other Global War on Terror Operations Since 9/11,” RL33110, Congressional Research Service, March 29, 2011, Table 3. Data for FY2011 is for continuing resolution, for 2012 is Administration FY2012 request. Deflated by CPI-all. CPI for 2011 assumes September 2011 m/m inflation is the same as August 2011 m/m inflation. Assumes 2012 inflation is equal to August 2011 CBO forecast for CY2012 inflation.
Figures 2 and 3 incorporate only direct fiscal costs to the United States government, and excludes interest costs. See here for another tabulation.
To recap, the $61 billion war  ended up costing (through FY2012) an estimated 874 billion, in FY2010 constant dollars. To place this in more current context, this works out to approximately 934 billion, in FY2013 dollars.
Given this investment, one might conclude that we cannot allow the sacrifice of treasure (and blood, see here) be in vain. However, economic theory suggests that sunk costs should not be considered in evaluating whether an enterprise should be undertaken. Rather, the (realistically appraised) costs and benefits of given options should be compared — that is a prospective evaluation is called for.
Moreover, this debate should be explicit and public. That is because, should Iraq descend into chaos or break up, there will doubtless be recriminations emanating from certain circles (well, they’re already emanating). In this regard, we do not need a replay of the “Who Lost China?” debate (as if it was America’s to lose), which distorted American foreign policy for decades.