The reason they are holding back on Obama is that they allowed it with Bush. They passed the Patriot Act, which gave the president and government more power than allowed by the Constitution.
They are trying not to look like--it was okay for one guy, but not the other guy, or--it was okay for a white republican, but not a black democrat. They painted themselves into a corner.
There is also the issue of back-scratching. McCain was never an Obama fan, but suddenly he turned into a major Obama cheerleader. Look at which Senators who normally went after Obama, are now supporting him. Even Boehner is approaching at a less than aggressive angle. Many members of Congress own stocks in corps like Keystone, or oil companies that will benefit from Keystone. Kerry owns a million worth of stock in Unitedhealth Group, a medicaid and medicare insurance company. The ACA forced Medicaid to take in over 4 million more people--the in-betweens, thus increasing stock revenues. Obama owns pharmaceutical stocks, hence the ACA push--that is an assumption on my part that his ownership in big pharm motivated his push for the ACA.
What will you give me if I back off this, that, or the other.
Boehner is just giving Obama a warning, of sorts. This is what I will do to you unless you give me something I want. In the law enforcement field, it is called extortion. In politics, it is called business.