The GOP is a lost cause.
On the other hand when the democrats were a minority or before 2007 and a majority in 2007-2008 they could not stop some of their Senators and Representatives from voting with Republicans and President Bush on important votes such as funding the war and the voting for the surge. So they do not have the great party discipline that you think.
It is almost impossible to have 100% of your party with you on most issue. You will always find few who will vote against the party.