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Sen. Ted Cruz criticized the "collapse" of the Obama administration's foreign policy and spoke of the dangers the Islamic State of Iraq and Syria (ISIS) poses to Christians and Israel at a gathering of social conservatives in Washington.

"Abroad, we see our foreign policy collapsing and every region in the world is getting more and more dangerous," Cruz said at the Faith and Freedom Coalition's conference in Washington.

"[ISIS'] stated objective is to create an Islamic caliphate that runs from Syria to Iraq and then to work to exterminate Jordan, Israel and, ultimately, America," he said.

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Cruz declined to offer any particulars for a policy in Iraq against ISIS, maintaining the cautious route he and fellow tea party Republican Sen. Rand Paul, R-Kentucky, have adopted throughout the week as the situation in Iraq worsens.

But speaking on the Senate floor after President Obama announced plans to send 300 military advisers to Iraq, he said the White House should seek congressional approval.

"If the president is launching or planning to launch a concerted offensive attack and is not constrained by the exigency of the circumstance, he should come to Congress to seek and receive authorization," Cruz said.

Cruz also criticized Obama for his failure to secure the release of Christians imprisoned abroad, including Meriam Ibrahim, a 27-year-old Sudanese woman jailed in Sudan and charged with apostasy and adultery.

Ibrahim, who is married to an American citizen, was sentenced to death for refusing to renounce Christianity.

"The president of the United States should stand up and speak on Meriam Ibrahim's behalf," Cruz said, to applause.

Sen. Marco Rubio, R-Florida, who also spoke at the event, made no mention of Iraq only a day after making the case for intervention on the Senate floor.

"Never again can we allow an al Qaeda-style group to establish a safe haven where they can plot against us anywhere on this planet," Rubio said Wednesday.

Instead, he played to the crowd, focusing on the importance of faith and family values to American politics.

"No matter how much we spend or reform … we cannot have a strong country without strong people," Rubio said. "And we will never have strong people without strong values."

ABC News' Chris Good contributed to this report.