How low can Bush’s approval rating go?  The CBS lede paragraph says it all:

Bush’s low job approval is far below that of some of his two-term predecessors at this point in their second terms. In November 1985, President Reagan had a 65 percent approval rating, and Bill Clinton’s job approval in November 1997 was 57 percent. Bush’s rating is higher than Richard Nixon’s was at the same point in his administration.

"Yeah, but he’s embroiled in a second-term scandal", you cry.

Yeah, and so were Clinton, Reagan, and Nixon.  But Clinton and Reagan never went below 40% (in fact, Clinton never went below 50%).  Compared to Bush, only Nixon — and even then, only at the very height of Watergate (January through resignation in 1974) — was lower.