After Donald Trump's victory over Ted Cruz Tuesday night, absent a particularly well-timed act of spontaneous human combustion, the unthinkable has happened: Trump will be the GOP nominee facing off against Hillary Clinton in November 2016.

Whether you consider this a welcome development or are as horrified about it as I am, the question to ask is: Why did the Republican so-called "Establishment" fail to rally behind Ted Cruz, the last man standing between Trump and the nomination?

Trump represents a 180-degree turn from where party leaders were pledging to take the party after President Obama's re-election victory over Mitt Romney in 2012, especially with regard to immigration and outreach to women and minorities. So why the curious lack of resistance?

Quite simply, it all comes down to Cruz.