House Oversight Committee chair Darrell Issa has made up his mind about what happened within the Obama administration as it crafted talking points about Benghazi last September. He just can't quite prove it. So on Tuesday, Issa subpoenaed all the Benghazi talking points-related emails from 10 State Department aides, because the emails are "critical to our effort to understand how and why officials at the State Department, the White House, and other agencies revised" them.

The email that Republicans originally thought was a Benghazi smoking gun turned out not to be one. Earlier this month, they released to ABC News' Jonathan Karl what seemed like emails from White House advisor Ben Rhodes saying the talking points needed to "reflect all agency equities, including those of the State Department." It turned out to be a summary of the email, which changed its meaning. Rhodes actually said the talking points needed to be resolved "in a way that respects all of the relevant equities, particularly the investigation." That means Issa needs more Benghazi material to work with. He already has his conclusion: "Publicly available information about the talking points creates the appearance that Administration officials were interested in sparing the State Department from political criticism in the wake of the attacks," Issa wrote in his letter to Secretary of State John Kerry on Tuesday. Issa made this conclusion at least a month ago, when he signed a House report saying the same thing: "to protect the State Department, the Administration deliberately removed references to al-Qaeda-linked groups and previous attacks in Benghazi in the talking points used by Ambassador Rice."

All Issa needs now, apparently, is the evidence.

"The documents the enclosed subpoena covers will help the Committee understand why, although on the day after the attacks senior State Department leadership believed that Islamic extremists were involved, there were reservations about publicly acknowledging any such involvement just three days later," Issa's letter says. But the committee needs more than State Department emails to figure that out. From the 100 pages of emails about the talking points released by the White House, we know that it was the CIA deputy director Mike Morell who took out references (right) to the CIA's warnings that terrorists could attack the diplomatic post. Why did he do that? To protect the investigation? After relentless badgering from the State Department? To know for sure, the committee needs CIA emails, too, doesn't it? Perhaps the CIA has provided them to Issa, and Issa hasn't made that public yet.

In fact, the result of Issa's investigation has been to raise more and more questions about the CIA's role in Benghazi. As we found out several weeks after the attack, the Benghazi post was a CIA installation. The CIA created the talking points. Rep. Dutch Ruppersberger requested them, fearing that newer lawmakers would accidentally release classified information, and then-CIA director David Petraeus went far beyond Ruppersberger's request to, in The Washington Post's analysis, shield his agency from recriminations. The CIA wrote that the Benghazi attack was inspired by protests in Cairo, which Susan Rice repeated, and which was not true. The CIA contractors who died in the second wave of the Benghazi attack, The Daily Beast reports, might have accidentally led militants to the CIA annex in Benghazi when they evacuated the main site. It's not clear whether the militants knew about the annex before hand, our found out by following the rescue convoy.

Issa writes, "I prefer to advance the Committee's investigation without having to use the compulsory process to obtain the entire universe of documents that the Department has withheld from Congress. With that in mind, the enclosed subpoena is narrowly tailored to cover documents and communications related to the Benghazi talking points." Maybe it's too narrow.