In 2008 there was one conservative candidate that was on the side of the citizens and against amnesty, Duncan Hunter.
They needed other “conservative” candidates to marginalize Hunter and nominate Mr. Amnesty himself, John McCain.
Fred filled one of those roles.
In every election since the last amnesty, only amnesty candidates have been nominated by the GOP.
This time they got Trumped.
It was supposed to be Yeb!’s turn.
Duncan Hunter's campaign wasn't going anywhere. Neither was Tom Tancredo's, and Tancredo was a much more identified with the immigration issue.
It might look now like immigration amnesty was always the biggest issue, but it wasn't back then. There was a lot of grassroots support for Fred Thompson, but his heart just wasn't in it.
Fred was out pretty early. He gave up in January. McCain had the nomination wrapped up by March (according to Wikipedia). If there was strong opposition to McCain or if immigration had been a big issue, the nomination wouldn't have been settled so early.