The Capitol dome is seen Hill in Washington, April 6, 2011, as work intensifies in Congress to reach a deal on long-overdue legislation to finance the government through the end of September and avoid a shutdown. (AP Photo/J. Scott Applewhite) (J. Scott Applewhite/AP)

Congress returns to Washington this week to confront some of the most substantive and politically nettlesome issues lawmakers will face between now and the November election.

Unless Congress acts, the interest rate on federally subsidized student loans will jump from 3.4 percent to 6.8 percent on July 1, raising the cost of college for millions of students.

On the same day, without congressional intervention, a short-term measure funding the nation’s highway and bridge-building program will also expire, forcing construction workers off the job.

Lawmakers will have two short weeks to set aside partisan rhetoric and maneuvers on both issues and find compromises — or face consequences of their inaction that could affect both parties with a major election just four months away.

And in the midst of those two debates will come a highly anticipated ruling from the Supreme Court on the constitutionality of President Obama’s health-care law. Whatever the court decides, the ruling probably will spike the partisan tensions and consume Capitol Hill’s attention for days, making deals on other issues even more difficult to achieve.

Trying to get ahead of the ticking clock, a conference committee of senators and House members has been negotiating for weeks to come up with a compromise over a $109 billion two-year highway funding bill.

The talks continued last week, even as the House was out of town on a one-week recess. With the House’s return Monday, negotiations will restart in earnest.

The tone of the discussions has so far fluctuated between conciliatory and confrontational. A key sticking point that remains is whether the bill will include language included in House measures to lure conservative votes that would require the White House to approve construction of the Keystone XL oil pipeline in Nebraska.

The negotiations appeared to take a turn for the worse last week, as Senate Democrats rallied with union workers in front of earthmovers just outside the Capitol and lead negotiator Barbara Boxer (D-Calif.) declared that House Republicans were “standing in the way of progress,” a theme that appears to be an emerging Democratic refrain.

In response, Rep. John L. Mica (R-Fla.), chairman of the House Transportation and Infrastructure Committee, accused the Senate on Thursday of failing “to offer any substantive cuts to bureaucratic red tape associated with building a highway or bridge” or movement on the oil pipeline.

House Speaker John A. Boehner (R-Ohio) has already raised the possibility of another short-term measure if a deal can’t be reached, an agreement under which highway projects would remain funded for six months.

That outcome would keep workers on the job but prove a bitter disappointment to lawmakers who fear another extension would let the nation’s Highway Trust Fund run nearly dry.

On the student-loan issue, the public’s verdict is likely to be especially harsh if Congress failed to reach agreement since leaders in both parties have repeatedly said they agree on the fundamentals.

Obama has conducted a series of college campus rallies to push to freeze rates for another year. Republican presidential candidate Mitt Romney has said he concurs — as has Senate Majority Leader Harry M. Reid (D-Nev.) and Boehner.

Yet leaders have been unable to agree how to pay for the nearly $6 billion price tag and have traded insults on the topic for weeks.

The GOP-held House passed a bill to pay for the item with cuts to the health-care reform effort. It died in the Senate. A Democratic alternative to pay for it by closing a payroll tax loophole for some wealthier small business executives was also blocked in the Senate.

Republican leaders recently proposed a series of other ways to pay for keeping loan rates low that borrowed from Obama’s budget proposal.Reid responded with an counteroffer that would fund the rate extension by changing how businesses calculate their pension liabilities.

“I feel fairly confident we’ll get that done,” he said last week.

But a path forward is not yet clear.

A spokesman for Boehner said the House has already passed legislation on the issue and will consider new proposals once they pass the Senate, putting the onus for a deal on Reid and Senate Minority Leader Mitch McConnell (R-Ky.).

McConnell has repeatedly called on Obama to get more involved in negotiating a deal. But Obama indicated in a speech at the University of Nevada at Las Vegas earlier this month that getting an agreement is Congress’s responsibility.

Sen. Bob Corker (R-Tenn.), a frequent critic of Congress’s tendency to conduct weeks-long fights over issues that will inevitably be resolved, said there will be a deal. But he maintained it could come to the detriment of taxpayers helping to subsidize ultra-low-interest loans to young people with little credit history.

“This is going to happen. Both presidential candidates want it to happen. It will happen,” he said. But, he added, “it’ll be done in a way that’s terrible policy for our country.”