Corker's bill was an alternative to the Kirk-Menendez bill, which also would have required the 2/3 vote override. Obama said he would veto either, if they passed.
Corker's bill was considered to have the best chance of getting the 2/3 vote needed to override Obama's veto.
Corker's bill would became the preferred bill after Mossad said they opposed Kirk-Menendez, in Jan 2015. Because of Mossad's position, several Senators(including McCain and Graham) would shift their support from Kirk-Menendez to Corker.
The underlying problem with both Corker's bill and Kirk-Menendez is that some(enough) democrats think that the GOP is trying to politicize the issue.
> “Corker’s bill was considered to have the best chance of getting the 2/3 vote needed to override Obama’s veto.”
Tabling either bill would have been preferable.