Thank you guys.
That rule strictly applies to
"The number of " -- singlular
"A number of " -- plural
The majority can be plural or singluar depends on the situation.
The majority of students are going to picnic.
A student majority is not participating in school election. -- is this correct sentense?
So in the same way "congressional majority" represents group and not group of things/people/ so it is singular right?
'The majority' by itself is always singular.
Her majority was five votes.
His majority has been growing by 5 percent every year.
The majority elects (not elect) the candidate it wants (not they want)
Please note as in my previous post I am not using the preposition 'of'.
When we use 'of', as done in your example it goes by the group, on whether the group is considered as a whole or as a set of people considered individually.
The majority of the voters
live (not lives) in the city.
The majority of students
are going to picnic.
Yep I do agree with every one that 'A majority' is singular. I couldn't imagine how it can be plural...