President Obama in a wide-ranging press conference on Tuesday looked to reassert his clout with Congress, as he faces growing questions about his ability to sway lawmakers 100 days into his second term.

Obama fielded questions on the response to the Boston bombings, chemical weapons in Syria, implementation of his health care overhaul, his inability to close Guantanamo Bay and even National Basketball player Jason Collins coming out as gay.

But the political message behind the rare presidential press conference — with Congress out of town — was clear: Obama looked to shake the notion that he can’t break through on Capitol Hill.

“Rumors of my demise might be a little exaggerated at this point,” Obama said with a nod to author Mark Twain.

And later, he placed the blame solely on Congress for Washington’s inability to move past continual gridlock.

“You seem to keep suggesting it’s my job to get them to behave,” Obama said defensively. “That’s their job.”

Obama’s press conference came against the backdrop of the 100th day of his second term, an early barometer for his job performance. In the past three months, Obama has seen his push for new gun restrictions die on Capitol Hill and still faces an uphill battle to implement other centerpieces of his agenda.

Foreign events, such as the likely deployment of chemical weapons in Syria, have also overshadowed the president’s domestic agenda.

Obama remained vague about whether his so-called red line in Syria had been crossed, calling again for a thorough investigation into whether President Bashar al-Assad had used such weapons against his own people. Initial U.S. assessments point to the use of the nerve gas, sarin, but Obama resisted calls to commit to an American military response.

If the red line was crossed, Obama said only that it would force him to “rethink the range of options available to us.”

And Obama was questioned about Guantanamo Bay, the American prison in Cuba where detainees have remained for years and are now engaged in a hunger strike despite Obama’s pledge to close the facility.

“Guantanamo is not necessary to keep America safe,” Obama said. “It needs to be closed.”

However, the president took no responsibility for Guantanamo, saying Congress had repeatedly blocked his efforts to shutter the prison. Obama vowed to push again for Guantanamo’s closure.

The implementation of Obamacare is perhaps even more important to the president’s legacy than his stalled push for greater gun control and his calls for immigration reform. Public polling shows that even Democrats are beginning to sour on the reforms, a trend the president looked to mitigate on Tuesday.

The president said that most Americans are “experiencing the benefits” of Obamacare even if “they don’t know it.”