What is meant by the ordering/ranking of members of Congress?

[LeftishBrit]

I keep seeing Santorum described as "the No. 3 Republican in the Senate' . What does that mean? That he has the third highest-ranking job (and what would that be?) or he's been there the third-longest, or what? MPs here aren't ranked in that sort of way, and I'm a bit unclear about what it means.

[onenote]

1. depends

It could be seniority. More likely its a reflection of position. Majority leader, majority whip, etc.

[UrbScotty]

2. It's ranked by their job

http://en.wikipedia.org/wiki/List_of_current_United_States_Senators#Leadership

[TechBear_Seattle]

3. As far as I recall...

Oops, what ih8thegop wrote in post #2. I'm guessing, then, that Speaker of the House and President Pro-Tem of the Senate do not count as positions of party leadership.

[Jim Sagle]

4. In his case, number 3 is the sum of number 1 and number 2.

:-)

[LeftishBrit]

5. Thanks for info!