Conrad Burns, possibly JD Hayworth... look at the vote spread... libertarians put Harry Reid in charge of the Senate.
"What leftists love about libertarian voters is that they elect democrats....."
"That is generally not the case."
When and where it is "generally not the case" it is only so because the GOP candidate or the Dim candidate win by margins that far exceed the votes of the Libers; not because the Libers failed to mount a candidate and not because the die hard Libers voted for the GOP.
But the fact is that there are a growing number of Libertarian minded conservatives in the GOP, particularly from western states, who, would be able to advance Libertarian ideas with greater ability if more Libertarians went to the mat fighting for position in the GOP (beginning in the local party orgs) for a place, as the social conservative values voters did for over 20 years. The fact is that many Libertarian's would sometimes find allies for their positions in the GOP, among other-minded conservatives and "moderates" at times. Outside the GOP, they are not in government and have no one to make policy alliances with.
The Libers and some other "purist" conservatives hate the glass half empty of a big, diverse GOP (in which you do get allies to vote with you some of the time) and prefer the glass totally empty outside of government. Thus, they never get the ability to demonstrate their ideas in practice. Thus, they cannot attract large non-activist members.