Making sense of House of Cards Season 3 - or trying to

Still bucking the critical trend and enjoying the deliciously cynical Netflix House of Cards Season 3, though finishing episode 9 have to admit having trouble retaining all of the details of the myriad plot lines. What's up with "Rachel", for example? Doug has been hounding his source at the FBI to give him info on Rachel's locale, and in this episode (spoilers) the source gives him a packet of materials showing that Rachel is a "Jane Doe" recently found murdered in the SW. This devastates Doug - he obviously has a romantic yearning for Rachel, and it's not clear if he even recollects that she's the one who beat him unconscious with a rock (as he was trying to relocate her for her safety - Season 2). So who murdered her? Is it just a coincidence, or did some minion of Underwood do so - as they want her out of the picture because of what she knows about Underwood's crimes? I'd thought Doug was trying to find her to rat her out to Underwood's minions, but perhaps not - maybe he was trying to find her to warn her and protect her, though how he could have done so is mysterious. Anyway, Doug is now off the deep end. The presidential campaign is a little confusing as well - obviously, Frank Underwood (Spacey) has changed his public position and is running for election; is Congresswoman Jacky his running mate? It sometimes seems as if she's running for prez, not veep. And nobody runs for veep anyway, so that's very confusing, at least to me. The most solid plot line by this point in the season is the U.S.-Russia conflict over the peacekeeping mission in Israel. The tension between Underwood and Russian prez "Petrov" is great, and it's interesting to see Claire U. (Robin Wright) learn the ropes of diplomacy. She does a great job humiliating the Russian UN ambassador and making her point: Don't fuck w/ me. I still think she will emerge as a presidential contender in her own right, either this season or next.