Continuing the bounce polls indicate he is experiencing in most states West of the Mississippi, John McCain now holds a 17-point advantage in South Dakota, 54 to 37 percent, according to a September 9th Rasmussen poll of 500 likely voters.

Back in July, a Rasmussen survey had McCain up by just 4 points over Barack Obama, 44 to 40 percent. However, like in the neighboring states North Dakota and Montana, the “Palin effect� has turned what appeared to be a dead-heat into a comfortable double-digit lead for the Arizona Senator.

Even though (or perhaps because) South Dakotans overwhelming believe Sarah Palin is “very conservative� (50 percent) compared to those who believe Biden is “very liberal� (30 percent), the state is quite supportive of McCain’s pick of the Alaska Governor. Fifty nine percent of likely voters say she was the right choice for McCain, with just 31 percent in disagreement.

Perhaps equally importantly, only 32 percent of South Dakotans believe Joe Biden was the right choice for Obama, with 39 percent in disagreement and many still unsure (29 percent). (Hillary Clinton won the Democratic primary in South Dakota back in June).

It is the Republican Party’s hope that voters energized by Palin will not just propel McCain into office, but also give a boost to Republicans down the ballot and the Party overall. The new Rasmussen poll finds George W. Bush getting his highest marks in the state this year with a 38 percent approval rating – up 5 points since July.