Story highlights Clinton delivered a blistering assessment of Bernie Sanders' credentials and readiness to be President

Clinton's campaign also released a video where a senior policy aide argues the Vermont senator "just hasn't thought it through" on Iran

Part of the speech will be used in an ad as well

Indianola, Iowa (CNN) Hillary Clinton delivered a blistering assessment of Bernie Sanders' credentials here on Thursday and implored Iowa voters to scrutinize his policies and readiness for the White House, declaring, "Theory isn't enough. A President has to deliver in reality."

It was the most forceful and direct contrast Clinton has drawn with Sanders yet, a speech that underscored the increasing urgency and acrimony of the race. From health care to foreign policy, Clinton repeatedly referenced Sanders by name and questioned whether his ideas could ever become reality.

"I am not interested in ideas that sound good on paper but will never make it in the real world," Clinton said. "I care about making a real difference in your life and that gets to the choice you have to make in this caucus."

Clinton acknowledged that while she and Sanders "share many of the same goals" they have "different records and different ideas on how to drive progress."

The former secretary of state used a Teleprompter to deliver her remarks to hundreds of supporters on the campus of Simpson College. The speech, one adviser said, was designed to "shake some sense into Iowans" and escalate the experience argument she has been making against Sanders with limited success.

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