Currently the biggest opponent for helping Ukraine seems to be the White House.
This article says Susan Rice of the White House has been stopping sending weapons to Ukraine clashing with General P. M. Breedlove over it. http://www.nytimes.com/2015/02/02/world/us-taking-a-fresh-look-at-arming-kiev-forces.html?_r=0
This FT article requires registration http://www.ft.com/intl/cms/s/0/7cfc8ac6-ab17-11e4-91d2-00144feab7de.html
.. but the relevant part there is that the Congress is willing to help Ukraine, but the White House opposes.
Yes, both Senate & House voted to help Russia. Obama changed to send MRE & blankets. Remember, ‘hot mike’ incident President Obama After My Election I Have More Flexibility?
President Obama: ON ALL THESE ISSUES,but particularly missile defense, this, this can be solved but its important for him to give me space.
President Medvedev: Yeah, I understand. I understand your message about space. Space for you
President Obama: This is my last election. After my election I have more flexibility.
President Medvedev: I understand. I will transmit this information to Vladimir.
I beleive Ukraine was ONE of those issues!