What to expect, or NOT, when Congress returns

As summer winds down it's time for everyone's favorite moment: Congress returning to Washington!

Sarcasm aside (because almost no one actually likes Congress anymore), there is some serious business for legislators to address and very little time to do it. The House and Senate return Sept. 8 and plan to adjourn by the end of the month to hit the campaign trail full time for the November midterm elections.

That leaves around 10 or so official "working days" until the 113th Congress, among history's least productive, closes up shop until a lame-duck session in November. On top of the to-do list: Keeping the government open past Oct. 1 when funding for government agencies runs out.

The U.S. Capitol.
Tom Williams | CQ Roll Call| Getty Images
The U.S. Capitol.

The budget deal hashed out between Sen. Patty Murray, D-Wash., and Rep. Paul Ryan, R-Wis., set spending levels into next year but did not actually appropriate money.

And there is no chance of passing all the appropriations bills needed to keep the lights on into October. So both houses will need to approve a continuing resolution by midnight Sept. 30. Conventional wisdom is that with elections looming and the GOP tantalizingly close to retaking the Senate, cooler heads will prevail and we will not repeat last year's shutdown, which sucked at least $24 billion out of the economy, according to Standard & Poor's.

The conventional wisdom is probably right. But it's far from a certainty.

The biggest wild card remains President Barack Obama's plans for unilateral action on immigration reform. The White House continues to signal that the president plans to move forward with proposals to deal in some way with the 12 million current undocumented migrants in the United States.

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His proposals could be narrow—dealing just with the families of so-called dreamers—or they could be sweeping. But whatever Obama does, especially if it comes before the midterms, it will drive conservative Republicans crazy.

Already, Senate Minority Leader Mitch McConnell and Sen. Marco Rubio, R-Fla., have hinted at tying government funding to Obama's actions on immigration. Neither directly threatened a shutdown and both would like to avoid it.

Democrats are making hay out of their comments because they believe that blaming the GOP for even nonexistent shutdowns plays to their political advantage. They are right about that. Republicans suffered big drops in popularity following the last shutdown. No one in party leadership wants to repeat that heading into November.

The problem is that GOP leadership, especially in the House, has shown no consistent ability to rein in tea party hard-liners who will demand a confrontation with the president under any circumstances but will do so with rampant ardor should Obama go solo on immigration.

Rep. Steve King, R-Iowa, a firebrand on immigration, told The Des Moines Register that "all bets are off" on a continuing resolution if Obama "wields his pen and commits that unconstitutional act to legalize millions."

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Republicans may find themselves at difficult cross-purposes with House members demanding a showdown in part to drive up turnout among base voters with more temperate members of the Senate fearing a backlash in critical statewide races that will determine control of the upper chamber in the 114th Congress.

Republicans are not exactly running away with swing state Senate races though they maintain a solid chance of picking up the six seats they need. Any fresh national disgust with shutdown politics could close off GOP chances to take Democratically held seats in states including North Carolina, Louisiana and Arkansas.

In addition to funding the government, Congress will also turn again to the issue of corporate inversions, with competing measures from Republicans and Democrats to try and address the issue.

Republicans led by Sen. Orrin Hatch of Utah favor a bill that would attempt to close off tax benefits from inversions but would not be retroactive to cover deals already in the works or completed. Democrats are demanding retroactivity.

These differences and others on exactly how to address the tax benefits mean no legislation is likely to come out of Congress. That, in turn, will put pressure on Obama's Treasury Department to come up with its set of executive actions addressing inversions through the tax code.

Administration sources say the White House remains very likely to roll out proposals by October (in time for the midterms), though whether they actually try and immediately enact those proposals remains an open question.

Because if they do, lawsuits are almost guaranteed and the matter could get held up in the courts for months. That would also complicate any future efforts to enact the kind of broad-scale corporate tax reform that all sides say they want and that would make inversions much less attractive.

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The CR is among the few "must-pass" bills the 113th Congress will face. The rest of the time will be taken up with purely political efforts including Senate votes on things like the minimum wage, pay equity and other issues they think poll well for them but have no chance in the House.

The House GOP will focus again on rolling back Obama administration environmental regulations, approving the Keystone pipeline and other issues the base loves but have no chance in the Senate. Most of that you can safely ignore. And you can probably bank on there being no shutdown but there are too many variables to put the likelihood at zero.

—By Ben White. White is Politico's chief economic correspondent and a CNBC contributor. He also authors the daily tip sheet Politico Morning Money [politico.com/morningmoney]. Follow him on Twitter @morningmoneyben.