This message board is about future planetary exploration and the political factors that enable it or prevent it. From what I can tell of the budgeting process for NASA, the White House and Congress decide on a top level figure for NASA and divide that amount of money among competing programs such as the manned spaceflight program and the planetary program. (There's some give and take -- NASA appears to develop bottoms up budgets to take to the negotiations with the White House about the top line budget.)
An article at Spaceflight Now nicely summarizes the impossible situation the manned spaceflight program is in. The White House and Congress may decide to provide more money to NASA to help resolve these problems. Even if they do, the pressure to move money from the science side of NASA -- which includes the planetary program -- is likely to be intense. My prediction is that the planetary program will gradually shrink over the next decade. I hope that the Decadal Survey includes that possibility in their prioritization of planetary missions.
A couple of more nice summaries are on Space Politics and Space.com.