Weigh in on something!

[blackdragon]

I read a piece of information of the U.S president's election, and i found out the phrase "weigh in on Obama's win".
I have searched the phrase of WEIGH IN, which was defined as "to argue st forcefully". i know, the phrase "weigh in on" has different meaning, but i would like to know the precise meaning of the phrase.
thank you so much!

[5jj]

It is difficult to know the precise meaning of the of the phrase without more context.

[emsr2d2]

I read a piece of information of on the U.S president's election, and I found out the phrase "weigh in on Obama's win".
I have searched the phrase of WEIGH IN, which was defined as "to argue st forcefully". I know that the phrase "weigh in on" has a different meaning, but I would like to know the precise meaning of the phrase.
Thank you so much!

Blackdragon, please look at the amendments I have made to your post in red. It is important to remember to capitalise the word "I" at all times, and to start every sentence with a capital letter.

I agree with 5jj that more context is needed to be certain, but my initial response is that it means to join in with a discussion about something. It can mean that the person is expressing particularly forceful argument.

John: All foxes are red.
Jane: No, they're not. Some are white.
John: Don't be ridiculous. They're red. I've seen them.
Jane: You haven't seen all foxes.
John: I've seen the ones in my garden.
Jane: But what about the ones in the Arctic?
John: I've never been to the Arctic, but I'm sure all foxes are red.
Susan: Stop arguing, you two! There are foxes of many different colours.
John: Oh, now you're weighing in on the subject, are you? Great, two women arguing against me!

In the above dialogue, Susan suddenly "weighed in" on the argument about foxes. She gave her opinion on an ongoing subject.

[etep]

It could also mean to introduce an opinion or a statement into an argument/discussion.

[Barb_D]

I disagree that "weighing in" must be done forcefully. Simply offering an opinion is weighing in.