All Cruz's amendment to the 2013 Gang of Eight bill proposed was increasing the cap on H1B visas, not mandating that number. Despite the arguments of protectionists, there is a shortage of STEM workers, a problem we as a society created. Cruz's amendment provided greater funding for domestic STEM education. In the short term, immigration is the only solution, other than offshoring.
When has the cap ever not been reached?
Despite the arguments of protectionists, there is a shortage of STEM workers
No there is not:
In fact, the nation graduates more than two times as many STEM students each year as find jobs in STEM fields. For the 180,000 or so openings annually, U.S. colleges and universities supply 500,000 graduates. - http://issues.org/29-4/what-shortages-the-real-evidence-about-the-stem-workforce/
And many H-1Bs replace American workers - who are required, as a condition of getting their severance, to train those replacements (e.g., http://www.amren.com/news/2015/02/southern-california-edison-it-workers-beyond-furious-over-h-1b-replacements/) - so where's the "shortage"?