Politics does, indeed, make strange bedfellows. Republicans in the Senate are lining up behind President Obama on the issue of granting him fast track authority to ram the Trans Pacific Partnership trade bill through Congress, while Harry Reid and the Democrats are opposing him.

While the unions and many liberals oppose the deal entirely, Reid's opposition to fast track authority for the president is more procedural than ideological. The Minority Leader wants to include 3 other minor trade bills in a package that would go to the president's desk. Majority Leader McConnell is opposing combining the other trade bills with fast track, largely because of opposition by most Republicans to one of them.

The Hill:

Senate Democratic Leader Harry Reid (Nev.) is trying to block the pending “fast-track” trade bill and has asked his conference to demand that three other measures be included in the legislative package.

The Wall Street Journal reported late last week that Sen. Ron Wyden (Ore.), the senior Democrat on the Finance Committee, told colleagues in a lunch meeting that fast-track should be combined with the other bills, including a measure with controversial language cracking down on currency manipulation.

Republicans on Monday accused Wyden of backing out of a deal they assert he made with Senate Finance Committee Chairman Orrin Hatch (R-Utah) to pair fast-track with Trade Adjustment Assistance (TAA), but not the two other measures the Democrats are now demanding.

A Wyden staffer disputed The Wall Street Journal story.

The aide said his boss has said since the beginning of the negotiations that all four bills need to make it to the president’s desk. And while he has not insisted on putting them into a single bill, Wyden has asked for a guarantee that they all become law, the aide said. 

But with most Democrats now demanding that all four trade bills — fast-track, TAA, a customs enforcement bill and a package of trade preferences for African countries — move in a single package, Senate Majority Leader Mitch McConnell (R-Ky.) will have trouble rounding up enough votes. 

It’s unclear if the White House and GOP leaders can get the necessary 60 votes to advance the legislation. Senate aides on both sides of the debate anticipate a close vote.

Florida Sen. Bill Nelson, one of seven Democrats to vote for fast-track in the Finance Committee last month, said Monday afternoon he would not vote to end debate on the motion to proceed to trade legislation unless all four bills are combined.

He said the Democratic caucus is unified on the question, kicking the ball back into McConnell’s court.

Hatch and other Republicans do not want to tie the customs enforcement bill to fast-track because it includes controversial language penalizing trading partners that engage in currency manipulation.

Supporters of the trade deal are making the same arguments made at the time of the NAFTA deal:

TPA has been the major vehicle by which major free trade agreements over the last 30 years, including the seminal North American Free Trade Agreement (NAFTA) and others with Asian nations, have been approved.

These trade bills have lowered tariffs here in the U.S., thus benefiting American consumers (Wal-Mart's everyday low prices could hardly exist without trade) while expanding export markets for American producers.

Some believe that TPA takes legislative power away from Congress. But it doesn't. TPA simply facilitates negotiating a trade deal and puts it on a fast track that still requires congressional debate and an up-or-down House and Senate vote for final approval.

Republicans have a natural suspicion of what kind of trade agreement Barack Obama will deliver. He's proven himself to be anything but a shrewd negotiator when it comes to foreign affairs — think Cuba. And others worry that he could abuse his executive authority, as he's done on immigration, the IRS and the health care law. But any bad deal that Obama negotiates can and should be voted down by Congress on final ratification. Republicans have large majorities in both houses of Congress that serve as a backstop to prevent a bad bill. But without TPA the process stalls out altogether.

The White House has been lobbying for fast track authority with an intensity not seen since the Obamacare debate, say observers. It will be a very close vote and an Obama loss would provide further proof of his impotency even with his own party.