Vows to cancel a recess, hold a session late into the night or meet through the weekend have in recent years become standard parts of a Senate Majority Leader’s repertoire.

But for Majority Leader Harry Reid (D-Nev.), the threats of a chamber lockdown have become particularly common. And since he occasionally follows through, Senators in both parties are left wondering whether a portion of their long-awaited August break now hangs in the balance.

Reid reiterated this week that he’s not ruling out the possibility that the Senate may need some extra time to finish up its outstanding business this month and that Senators may need to remain in session through this weekend and possibly beyond next Friday’s scheduled start of the four-week August recess period.

What’s more, Reid also is crafting an aggressive schedule for much of the rest of the year. On Tuesday, the Nevada Democrat laid out an ambitious agenda for the Senate as he called to resume votes on Sept. 4, break for one week beginning Oct. 8 and then return full time through Nov. 16. The Senate may even return to business on Dec. 3, Reid warned, if lawmakers are unable to wrap up any outstanding work.

Those announcements come on the heels of last week’s threat — and delivery — of an all-nighter session on the Defense authorization bill and after more than six months of pledges to hold Saturday votes and to delay or call off various one-week recesses.

“There’s no guarantees in this business, especially at this time of year,” Reid said on the floor Monday. “We worked all night one night last week, we worked until early in the morning one night, and that may be necessary this week and next week. And I would hope that we can break in time for our recess, but again, as I’ve said now for weeks — we have to finish this work first.”

Neither Republicans nor Democrats want to bet on whether Reid will actually carry out his latest August warning given his previous willingness to extend the Senate schedule. At the same time, Senators in both parties say they are crossing their fingers they won’t have to disrupt a calendar that’s already filled with travel, constituent work and family events.

“I, for one, have the month of August completely planned,” Sen. Mel Martinez (R-Fla.) said.

Martinez said any extension of the calendar will certainly carve into his planned one-week vacation and three weeks of in-state activities. He added that Reid’s most recent threat to delay the break is unwelcome, especially in the wake of last week’s “pajama party” over the Defense bill and after numerous Monday and Friday votes on “meaningless” legislation.

“It’s irritating,” Martinez said. “It makes planning difficult and it interferes with your personal life.”

Although Democratic Senators seem far more willing to accept Reid’s directives over the Senate calendar, they too are hoping for a Friday adjournment. But they also defended their leader’s use of the schedule as a stick to pressure Senators to work together and efficiently to move legislation through the chamber.

“Everyone wants to go home,” Sen. Frank Lautenberg (D-N.J.) said. “But Harry Reid has every right to put the country’s needs forward. It’s not us who are the problem. It is they standing in the way and obstructing everything that’s going on. So it’s what we have to do.”

Reid’s penchant for threatening to draw out the Senate schedule comes as he faces increasing difficulty shepherding Democratic priorities through a near equally divided chamber. It also comes as his party’s nascent majority tries to demonstrate that it is harder-working than its GOP predecessors and that it is intent on changing the direction of the nation’s domestic and foreign policies.

Jim Manley, Reid’s spokesman, said his boss isn’t issuing “threats for threats’ sake.” Rather, Manley said Reid has made a concerted decision to use the calendar as a means to push for progress against a GOP minority that seems intent to “slow, stall and stop” Democratic initiatives.

“Sen. Reid has come to the conclusion as [Republicans] continue to waste the American people’s time, he will do what’s necessary to get our work done,” Manley argued.

“He acknowledges everyone wants to go home, but also they have to acknowledge Reid is serious,” Manley continued. “This is not about being popular, but about making decisions to get our work done.”

Indeed, even weary Democrats concede that Reid has to use whatever means necessary to move the Senate along, and even though they don’t necessarily like it, they back his decisions to delay scheduled breaks or burn the midnight oil to cast important votes.

“I support what the Leader is doing 1,000 percent,” Sen. Debbie Stabenow (D-Mich.) said. “We have so many important issues before us. If he doesn’t set deadlines and put our feet to the fire, it’s possible we’ll debate things endlessly.”

“Harry Reid genuinely wants to get as much done as possible this year,” Sen. Mark Pryor (D-Ark.) said. “He’s using every tool available in the Majority Leader’s toolbox to move legislation through the Senate.”

“No one wants to stay in extra days, I know that,” Pryor added. “If we’re here Monday, I — along with 99 other Senators — will have scheduling conflicts. No one wants to go into extra days, but if we have to, we have to.”

Reid’s posture during the first quarter of the 110th Congress isn’t occurring in a vacuum. Senate Republicans have crafted their major message offensive around an argument that Democrats are responsible for leading a “do-nothing” Congress — racking up few accomplishments and failing to deliver on promises.

And while the chamber’s schedule is generally under Reid’s purview, he could soon get a taste of his own medicine if conservative Republicans have their way.

Sen. Jim DeMint (R-S.C.) has warned Reid and GOP leaders that he will filibuster the ethics bill when it returns to the floor at the end of next week if changes to the bill’s earmark reforms are made. DeMint also has threatened to force the chamber to remain in session well past the start of the August recess.

Additionally, Reid’s plan to reconvene for an appropriations session in November could be derailed by DeMint and his fellow reformists, as the South Carolinian and Sen. Tom Coburn (R-Okla.) are expected to mount challenges to earmark-laden spending bills.

Even if they do some threatening of their own, Republicans are hoping that the “do-nothing Senate” message translates with voters, especially given that it was the same argument used against them before the 2006 elections that cost them the majority. With that in mind, many GOP Senators think Reid’s regular threats to hold them here are less about lawmaking and more for political advantage.

“In most cases it’s a lot of bluster and bombast,” Sen. John Thune (R-S.D.) said. “Most Republicans recognize that. [Reid] doesn’t usually follow through. It’s particularly for the public’s consumption. I understand what he’s trying to accomplish, but I don’t think it’s taken with a lot of seriousness around here.”

Sen. John Cornyn (Texas), the Republican Conference vice chairman, agreed and said Reid is racking up a “pretty long list” of threats so far this Congress, many of which haven’t been realized. At the same time, however, Cornyn said Reid knows what makes Senators sit up and take notice.

“Everybody has a schedule around here,” Cornyn said. “We hold it pretty near and dear. Maybe he feels that if he strikes fear in our hearts, we’ll be more compliant? I’m not so sure that works.”

John Stanton contributed to this report.