The new US Congress has convened. But as Democrats celebrated their increased clout, swearing in new members, plenty of challenges lie ahead.Future President Barack Obama wants backing for a massive economic stimulus package. There is also the expansion of health care to deal with as well as plans to withdraw US troops from Iraq and redeploy many of them to Afghanistan. Proceedings did not get off to an entirely smooth start in the Senate where the man picked to replace Barack Obama was denied entrance. Fellow Democrats have resisted Roland Burris’s appointment by Illinois’s scandal-scarred Governor. Burris said he was told by the chamber’s secretary that he could not take his seat. “I presented my credentials to the secretary of the Senate and (was) advised that my credentials were not in order and I would not be accepted and I would not be seated and I would not be permitted on the floor and therefore I am not seeking to have any type of confrontation,” he told reporters outside the Senate. “I will now consult with my attorneys and we will determine what my next step will be.” Burris was formally blocked because his Senate application was not signed by Illinois’s secretary of state who has refused to certify the 71-year-old’s appointment by Rod Blagojevich. Governor Blagojevich, who denies any wrongdoing, has been accused of attempting to sell the seat formerly occupied by Barack Obama.