Marco Rubio, from interview with Marco Rubio in the UK Guardian:

“The only way to defeat Isis is for Sunni Arabs themselves to reject them ideologically and defeat them militarily,” Rubio said. “They must be defeated on the ground with a ground force that is made up primarily of Arab Sunni fighters from Iraq, from Syria, but also from Jordan, from Egypt, from the Emirates, from Saudi Arabia.”......“Whatever it is, we’re going to do that. If you’re going to engage militarily, you have to ensure you have the resources to win, not simply to have a symbolic gesture. “So unlike this president, our troop strength in an effort like that will be determined by what’s necessary to achieve victory, not some artificial constraint or an artificial number that I make up in my own head.”

It has already become clear that the Islamist Kingdoms and Emirates of the Sunni Persian gulf are ideologically closely aligned with ISIS.

So much so that Op-Ed's arguing this point are being published in the staid and conventionally respectable pages of the New York Times.

See Saudi Arabia, an ISIS That Has Made It. Excerpt:

Black Daesh, white Daesh. The former slits throats, kills, stones, cuts off hands, destroys humanity’s common heritage and despises archaeology, women and non-Muslims. The latter is better dressed and neater but does the same things. The Islamic State; Saudi Arabia. In its struggle against terrorism, the West wages war on one, but shakes hands with the other. This is a mechanism of denial, and denial has a price: preserving the famous strategic alliance with Saudi Arabia at the risk of forgetting that the kingdom also relies on an alliance with a religious clergy that produces, legitimizes, spreads, preaches and defends Wahhabism, the ultra-puritanical form of Islam that Daesh feeds on.

Rubio's Islamic Dream is that the rich Sunni Islamists of the region and Gulf will join and be linked in battle with US infidels, fighting to the death against more radical but their ideological soul mates, Sunni Islamists of ISIS.

The biggest plus about ISIS for powerful Sunni rulers in Saudi Arabia, is that they are not Shiites, as Shiites are the ultimate regional enemy, controlling and being the dominant population in Iran and from Baghdad on south in the former Iraq.  Iran also supports Assad in Syria, who supports Shia Hezbollah in Lebanon, which have fought for Assad in Syria.

Additionally, Sunni's in Iraq's Mosul have little motivation to overthrow ISIS either, as it would put them back under control of the Shiite government of Baghdad.

The Iraq government run by Shiites has little motivation to free Mosul or beyond it would just bring more Sunni back into the government.  Essentially that would be Shia dying to free Sunni, their past oppressors.

So Rubio's Dreams are just that, delusional and/or intentionally deceptive blather misrepresenting the realities of the region, nearly as wild as similar fabrications used by the last Republican administration to start the war in Iraq in 2003.

Does Rubio dream that after Sunni defeats Sunni in Syria, that structures like the Shiite Mosque to Ammar ibn Yasir and Uwais Qarni will be rebuilt?  The mosque relates to the beginning conflicts of the great Muslim civil war, the Battle of Siffin in 657. It's destruction tells you about the chances of a Sunni - Shia rapprochement, or of Sunni fighting Sunni, and everyone living happily ever after in the region.

The Uwais al-Qarni was totally destroyed by the anti-Shia Muslim, Sunni Muslim, fanatics of ISIS on May 31, 2014 when they took control of Raqqah Syria.

The former Raqqah Shi'ite mosque before it was destroyed by Sunnis of ISIS.