Making it less and less likely that the Iran nuclear deal can be stopped in the Congress, Tuesday brought forth another series of announcements from Democrats in support of that agreement, as the White House rallied support from key Senators.

"It will stop Iran from developing a nuclear weapon for at least the next 10-15 years," Sen. Bill Nelson (D-FL) said in a speech on the Senate floor.

"The more we talk about the agreement, the more we realize there is no good alternative to the agreement," said Sen. Barbara Boxer (D-CA) to reporters just off the floor of the Senate.

The announcements on Tuesday from those three Democratic Senators followed a similar spurt of announcements from House Democrats on Monday, all of which had the aroma of a public relations blitz backed by the White House, in advance of a speech on Wednesday here in D.C. by President Obama in favor of the deal.

The news came as President Obama met with Jewish leaders at the White House, as officials lobbied for their support.

"He believes that this historic agreement to prevent Iran from obtaining a nuclear weapon isn’t just in the best interest of the United States, it’s clearly within the national security interest of our closest ally in the Middle East, Israel," said spokesman Josh Earnest.