Senate Foreign Relations Committee Chairman Bob Menendez (D-NJ) is making the best argument of all for a joint select committee to investigate the Benghazi scandal, Sen. Ted Cruz (R-TX) says: He admits he has no clue what President Barack Obama was doing during the terrorist attack.

Cruz duked it out with Menendez on the Senate floor on Monday over Cruz’s latest push for a joint select committee to investigate the scandal, prompting Menendez’s admission. Cruz has been arguing for a joint select committee–which would be bipartisan and encompass members of both the House and the Senate–for months.

When Cruz tried again to use a unanimous consent procedure to pass his joint select committee bill, Menendez jumped in to argue against it–saying that it’s “politically motivated,” which he said of the recently created House of Representatives’ select committee to be chaired by Rep. Trey Gowdy (R-SC).

After Menendez recounted the usual Democrat talking points about why Benghazi is no longer a scandal, he offered his own resolution pushing for unanimous consent that would provide additional security resources to embassies and consulates around the world per a recommendation from the ARB report. But during his speech against Cruz’s bill, he made a new argument–that Republicans are pushing for Benghazi truth because Obamacare is somehow, in his view, now popular.

“Their previous one-trick pony, repealing the Affordable Care Act, has finally been put out to pasture,” Menendez said. “Republicans desperately need another political trick, and apparently, when there is nothing else of substance to fire up their base, their plan is to yell, ‘Benghazi!’ as often and as loudly as possible.”

Cruz countered Menendez by noting the New Jersey Democrat “suggested that this is a request on the eve of a midterm election. The only reason for that is, of course, when I made the request eight months ago, the exact same request, the Democrats objected and blocked a joint select committee into Benghazi at that time.”

Cruz said:

The senior Senator from New Jersey also suggested that this was somehow to distract from Obamacare. I can promise you, there is no one in this chamber less interested in distracting from Obamacare than I. And indeed, I would encourage the senior Senator from New Jersey, if he believes what he said, to go and campaign for his Democratic colleagues who are up for election this year with the simple message that he said on the floor of the Senate, which is, “Senator so-and-so was the critical 60th vote to passing Obamacare, and if you like it, you should keep your senator.” I feel quite confident that the Democratic senators up for election this year are running as rapidly away from the points suggested by the senior Senator from New Jersey as possible.

Cruz pushed for a colloquy with Menendez at that point to ask him a few questions directly about Benghazi.

“Why is it, I am curious, that the senior Senator from New Jersey thinks an inquiry to ascertain the truth about what happened is necessarily a partisan endeavor?” Cruz asked Menendez. “Is there no partisan interest on that side of the aisle in finding out what happened and how it could have been prevented and why we didn’t save those four Americans?”

Menendez responded that Cruz’s ten questions about Benghazi–which he laid out in an earlier floor speech–are irrelevant:

[Cruz] suggested that his ten questions, because he makes the ten questions, are suddenly worthy of being answered, worthy of the fact of not being viewed through the prism of any politics. I would just say if there is political spin, several of your questions were pretty shocking to me in terms of the political nature of it. There is, as I said to the whole body, we have had a whole host of efforts to review the facts and come to the determination of what happened in that day–they have been in public hearings and they have been in secured intelligence briefings.

Cruz noted that Menendez “did not endeavor to answer any of the questions I proffered, including the most simple question, which is: ‘Did the President sleep on the night of Sept. 11, 2012?'”

Cruz said Menendez’s admission that he knows nothing about the President’s activities that night was a “powerful speech in support of this joint select committee on Benghazi.”

“The Democratic Senator from New Jersey, the chairman of the Foreign Relations Committee, just told this body that he has no idea if President Obama was even told four Americans were under terrorist attack,” Cruz said. “He has no idea. He doesn’t know what, if anything, the President could have done to save them.” 

Cruz added:

I would suggest that’s exactly the reason we need this committee. If the chairman of the Foreign Relations Committee, two years later, cannot answer that question, it makes abundantly clear that the response of the administration, and sadly the response of Senate Democrats, has been partisan stonewalling, rather than trying to get to the truth. In the immortal lines of Jack Nicholson, it makes one think perhaps they can’t handle the truth–or at least they don’t want to know it.

The first of Cruz’s ten Benghazi questions that still need answers is why the State Department would not provide the level of security forces requested during the summer of 2012. 

Cruz’s second question focuses on Obama’s intelligence briefings: “Why hasn’t the White House declassified and released those briefings, just like President George W. Bush did with his pre-September 11, 2001, briefings?”

Thirdly, he asked why the U.S. did not “anticipate the need to have military assets at the ready” in the Benghazi region as a whole on the anniversary of 9/11.

Cruz’s next question focused on President Obama and then-Secretary of State Hillary Clinton themselves. “Did President Obama sleep the night of September 11, 2012? Did Secretary Clinton? Neither has answered that very simple question,” Cruz said. “Were they awake or asleep while Americans were under fire?”

The next several questions focused on the talking points, the FBI’s activities in Benghazi after the attack, and the ARB report’s practices.

“Why have none of the terrorists who attacked in Benghazi been captured or killed?” Cruz asked for his ninth question, adding for his tenth: 

What additional evidence that the White House engaged in a partisan political campaign to blame the Benghazi attack on the Internet video is contained in the additional emails requested by Judicial Watch but withheld by the White House on the ground that it would put a “chill” on internal deliberations?

Instead of chilling internal deliberations, Cruz said that 20 months after the attacks, what he thinks is “truly chilling” is that “we have four dead Americans and no dead terrorists.”

“It is chilling to think that our President may have had better things to do than personally attend to an ongoing terrorist attack on our people,” Cruz continued. “It is chilling to imagine that we could have mounted a rescue attempt of our own people but that we didn’t even bother to try.”

WATCH: Cruz’s full floor speech and debate with Menendez over Benghazi: