WASHINGTON (CBSDC/AP) — Despite President Barack Obama’s low approval ratings, Republicans are still struggling to move ahead of Democrats to reclaim the Senate in November’s midterm elections.

In a piece authored by Larry Sabato, Kyle Kondik and Geoffrey Skelley for Politico this week, the authors state that Republican Senate candidates in toss-up states of Alaska, Arkansas, Iowa, Louisiana and North Carolina have yet to open up a real polling lead, and the summer is coming to a close to pull away.

“Sometimes tidal waves, such as the 2006 Democratic swell that gave the party control of both houses of Congress, develop in late September or October. That’s certainly still a possibility for the GOP in 2014. However, the summer is waning, and as Labor Day approaches our estimate remains a Republican gain of four to eight seats, with the probability greatest for six or seven seats—just enough to put Republicans in charge of Congress’ upper chamber. The lowest GOP advance would fall two seats short of outright control; the largest would produce a 53-47 Republican Senate,” they wrote for Politico.

Speaking to CBSDC, Sabato, the director of the Center for Politics at the University of Virginia, said that Republicans are having trouble pulling away from the pack due to their low approval rating.

“Voters have a low opinion of both congressional parties. In fact, the GOP is even lower than the Democrats in the public’s estimation,” Sabato explained to CBSDC. “Obama isn’t popular, but the Republicans in Congress are much less popular.”

A recent CBS News poll found that 62 percent of Americans did not view the Republican Party favorably, compared to only 29 percent who did. On the Democrats’ side, 41 percent polled viewed the party favorably, while 50 percent did not.

The job rating of Congress is much worse, the poll found. Only 15 percent of Americans approve the job lawmakers are doing, while a whopping 78 percent disapprove.

Another element that has hurt Republicans is talk about lawmakers possibly trying to impeach Obama. The House has passed legislation to block Obama from expanding Deferred Action for Childhood Arrivals and, through its power of the purse, could attempt to cut off the funds that would be needed to implement the expansion. House Republicans could also consider widening or amending their existing lawsuit against Obama over his health care law, a case both parties have suggested could be a prelude to impeachment proceedings.

“This talk is mainly confined to the fringe, but they get loads of attention,” Sabato told CBSDC about the impeachment talk. “Of course it hurts Republicans. Not only is it stupid from that vantage point, but it wasted capital on a project that has a less than zero chance of ever happening.”

The chairman of the Democratic Congressional Campaign Committee, Rep. Steve Israel, D-N.Y., said Republicans could end up in trouble if Obama’s moves on immigration increase calls for impeachment.

“The problem that Republicans have right now is that they have engineered a strategy to turn out their base voters in a midterm election and that may backfire against them as their base voters demand that House Republicans keep going farther and farther to the right,” Israel said in an interview with The Associated Press.

Senate Democrats seeking re-election in red states, including Arkansas’ Mark Pryor and North Carolina’s Kay Hagan, have cautioned Obama against proceeding unilaterally on immigration.

“This is an issue that I believe should be addressed legislatively and not through executive order,” said Hagan, one of the top targets for Republicans trying to retake control of the Senate.

Pryor, another vulnerable incumbent, said in a statement that he also is “frustrated with the partisanship in Washington. But that doesn’t give the president carte blanche authority to sidestep Congress when he doesn’t get his way.”

Obama said Thursday he still intends to act on his own to change immigration policies but stopped short of reiterating his past vows to act by end of summer.

Obama raised the slim hope that Congress could take action on a broad immigration overhaul after the midterm elections in November. He said that if lawmakers did not pass an overhaul, “I’m going to do what I can to make sure the system works better.”

But for the first time since pledging to act by summer’s end, he signaled that such a target date could slip. He said that the administration had been working to reduce the flow of unaccompanied minors attempting to cross the border and noted that the number of apprehensions at the border had fallen in August.

“Some of these things do affect time lines and we’re just going to be working through as systematically as possible in order to get this done,” he said in a news conference.

Sabato tells CBSDC it is unknown yet whether Obama taking potential executive actions on immigration will hurt Democrats come November.

“Obama is trying to stimulate a big turnout among Hispanics and other Democrats by exciting them with this, but those opposing liberalizing immigration rules will be infuriated and may well also turn out in large numbers,” Sabato said.

Republicans are already hinting they’ll consider legal action to thwart what they’ve denounced as a violation of the separation of powers. House Speaker John Boehner, R-Ohio, in a conference call this month with GOP House members, accused Obama of “threatening to rewrite our immigration laws unilaterally.”

“If the president fails to faithfully execute the laws of our country, we will hold him accountable,” Boehner said, according to an individual who participated in the call.

Sen. Bill Nelson, D-Fla., predicted Thursday that Congress would not tackle an immigration overhaul before the fall elections.

“There are too many members of the House that are scared of the tea party, and they are afraid to death that they won’t get the extremist support in the election,” Nelson told reporters in Orlando, Florida. “There is nothing being done on immigration until after the election, and probably not until we get a better sense of where we’re going into next year.”

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