[Hostage]

It doesn’t matter if the deal is voted be disapproved. Obama will veto Congress’ disapproval. This is the upside down logic Ted Cruz pointed out months back that Corker was so wrongheaded to package the Iran deal in this way because it would entail a 2/3’s vote in both chambers to override Obama’s veto.

Whereas if it had been crafted as a treaty as it should have been, it would have taken 2/3’s of the Senate to approve it.

[Jim from C-Town]

It denies Obama the legitimacy he desires. That is the reason why it must not pass.

[Ben Ficklin]

Corker's bill had nothing to do with the Iranian agreement not being a treaty.

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.