Democrats seem to be avoiding their earlier argument that passage of ObamaCare would create a bump upward in their polling — and avoiding talk of ObamaCare altogether, when they can manage it.  Two polls by Gallup this week show why.  Barack Obama’s weekly approval rating continued its drop to its lowest point ever at 47%, and Republicans once again took the lead on the generic Congressional ballot:

President Obama’s job approval rating fell to 47% for the week ending April 11, the lowest of his administration so far by one percentage point.

Obama’s weekly job approval average has fluctuated within the narrow four-point range of 47% to 51% since January of this year. The current weekly average more than anything else represents a continuation of the president’s generally lower approval ratings this year compared to the higher ratings he enjoyed in his first year in office.

On a short-term basis, Obama’s latest three-day average (Friday through Sunday) is at 45%, with disapproval at 48% — both of which are the worst three-day averages since Obama took office.

In the immediate days after the bill’s passage, Gallup showed a slight bump upward in Obama’s approval ratings, which Democrats hailed as the big comeback they’d predicted. But the overall direction of Obama’s approval numbers during the health-care debate has been plain to see. He started off with a 66% approval rating in May, as Nancy Pelosi readied the bill for consideration, and 59% in June when it was unveiled. He has lost a third of his support since its introduction, and Gallup reports that even among their sampling of the general adult population rather than registered or likely voters (a sample type that is traditionally more sympathetic to Democrats), ObamaCare remains unpopular.

For that matter, so do the Democrats. In the presidential poll report, Gallup notes that the approval level for Democrats has also dropped to a new low of 41%. After pulling back into a tie with Republicans on the generic Congressional ballot last week, the GOP surged ahead by four this week:

Gallup Daily tracking for the week ending April 11 puts Republicans slightly ahead of Democrats, 48% to 44%, in the congressional voting preferences of registered voters nationally. This marks the third week since the U.S. House passed healthcare reform on March 21 that the Republicans have tied or led the Democrats.

Gallup’s measure of voter support for the two parties’ congressional candidates asks respondents whether they would back the Republican candidate or the Democratic candidate in their own district if the election were held today. The results — when based on likely voters shortly before Election Day — have proved, historically, to be a highly accurate predictor of the national two-party vote. This, in turn, bears a close relationship to the post-election party division of House seats.

The trend based on registered voters shows how rare it is for the Republicans to lead on this “generic ballot” measure among all registered voters, as they do today. Other recent exceptions were recorded in 1994 — when Republicans wrested majority control from the Democrats for the first time in 40 years — and 2002, when the GOP achieved seat gains, a rarity for the president’s party in midterm elections. In midterm years when Democrats prevailed at the polls (such as 2006, 1990, and 1986), their net support among registered voters typically extended into double digits at several points during the year — something that has yet to happen in 2010.

The GOP maintained an 18-point lead on enthusiasm, although that measure tapered off somewhat for both parties after the passage of ObamaCare. Only 30% of Democrats are very enthusiastic about voting in the upcoming election, while 48% of Republican voters are champing at the bit.

Democrats and Obama didn’t get a bump. They got a slump.