After watching lawmakers agree to two bills this week dealing with guns and school safety in the aftermath of the school shooting in Parkland, Florida, Democrats say the gun violence marches around the nation on Saturday have the chance to change the political dynamic on gun control in the Congress.

"Their hope gives me hope," Sen. Bill Nelson (D-FL) said of students from Marjory Stoneman Douglas High School, and others who have joined in calling for action on gun violence.

"Their determination gives me determination," Nelson said at a U.S. Capitol news conference, even as he and other Democrats again acknowledged that they are far from having the votes to press ahead with gun control plans.

Among the plans that Democrats have focused on in recent weeks include:

+ The Manchin-Toomey 'universal background checks' bill, which would require checks for almost all private gun sales.

+ A federal law raising the minimum age to purchase a weapon to 21, mirrored on a law just passed by the state of Florida.

+ A ban on the sale of weapons like the AR-15.

+ Limits on high-capacity ammunition magazines.

"We have an important role to play in insuring that no students should ever be afraid to walk down the hallway of their school," said Rep. Ted Deutch (D-FL), whose district includes Parkland, Florida.

"It is our job, and everyone working in that building behind us, to pass laws, to keep our communities safe," Deutch said at a news conference outside the U.S. Capitol.

But the last five weeks were also a reminder of the difficulty of acting on any gun-related legislation - no matter how minor it might be.

The "Fix NICS" bill approved this week as part of a giant spending bill was bipartisan, yet it also had some sharp opposition from Republicans in the House.

And that makes the idea of the 'Buy 21' bill, or any ban on assault weapons, difficult to see getting through the Congress, unless there is major change in the makeup of the U.S. House and Senate.

"You know the politics, but you got to start somewhere," said Nelson. "This is the first step at the federal level."

"There is no better example of the youth of our country becoming engaged, than in this march," said Deutch.