White House Press Secretary Josh Earnest let Republicans have it during his daily briefing. He explained why they are the reason for Trump's rise by stating:
"Look, the Republican voters will decide who they believe best will represent their party. I think what is true is that there is some consternation within Republican circles at least within Washington, DC about the strength of Mr. Trump’s campaign, and the suggestion has been that he has, he is on the brink of succeeding and hijacking the Republican Party, but the truth is when you have party leadership in Washington, DC that is blocking important work that needs to get done, it’s not surprising to me that it’s not particularly challenging for the views of the party and its candidates to be a little unclear.
We see Republican leaders in Congress who spent years campaigning to try to get the majority in both the House and the Senate. Now they have that majority, and they’re in a position where they’re not just saying no, they’re not saying anything. They’re refusing to speak.
So again, it’s not surprising to me that a Republican majority in Congress is refusing to their job is on the brink of being taken over by someone who they say doesn’t represent their own views. If you don’t stand for anything, you’ll fall for anything."
Since many Republicans made it their only goal to obstruct Obama, it's easy to see why Donald Trump is taking over the Republican party.