The Liberal government is busy clearing the legislative decks before Parliament rises for the summer, trying to secure the smooth passage of its budget through the Senate despite some headwinds. But a review of the bills passed so far shows this government has been less legislatively ambitious than the one it replaced.

Just 23 government bills have so far passed through both houses of Parliament halfway through the four-year mandate. The former Harper government, by comparison, secured royal assent for 50 bills in the same time frame during their majority government, according to data supplied by the Library of Parliament.

The Liberal government has passed some substantial legislation, including:

In addition to the budget, one other piece of legislation — the establishment of a parliamentary oversight committee for Canada's security agencies — is expected to pass before the end of the month, bringing the total number of government bills passed to 25 in some 18 months.

Here is a list of three possible factors as to why the Liberal figures are so (comparatively) low?

1. 'Doing politics differently'

Prime Minister Justin Trudeau vowed to do politics differently during the last election campaign, allowing more free votes on some legislation (backbenchers took up his offer on Liberal Senator Jim Cowan's genetic discrimination bill) and by limiting the use of debate-limiting measures like closure and time allocation — a legislative manoeuvre sometimes called the "guillotine" because it formally limits the length of debate on a bill in order to force a vote.

Government House leader Bardish Chagger says her party has allowed 'greater discussion and debate of legislation.' (Adrian Wyld/Canadian Press)

At the end of the Harper government, those two tools had been used roughly 100 times in a four-year time period, according to the Library of Parliament. As of June 14, the Liberals have relied on them 23 times to move legislation along to the next phase. If there is less reliance on these measures, things take longer to progress.

"As we move to improve Parliament, we have allowed ... greater discussion and debate of legislation among members so that they can participate," Liberal House leader Bardish Chagger said in an emailed statement sent to CBC News.

"We believe it's better for Parliament because MPs from all sides get a chance to have their say and represent their constituents and debate legislation in a sufficient manner," she said.

2. The Senate

The low number of bills passed is also due in part to the new reality the government faces in the Senate, where there is a plethora of newly appointed Independent senators — men and women who do not sit in a partisan caucus, and take orders from no one.

As third-party leader, Trudeau abruptly cut loose all the Liberal senators from his national caucus at the height of the Duffy scandal. The remaining Liberal contingent thus owes no loyalty to the prime minister or to ensuring his agenda is expediently passed.

The government does have a "caucus" in the Red Chamber — made up of just three non-affiliated members.

Liberal Leader Justin Trudeau says 32 senators will sit outside the Liberal caucus as Independents 5:43

The new Independents, individuals plucked from positions largely outside the political world because of the push to appoint nonpartisans, are eager to leave a mark on government legislation. Not content to simply toe the government line, some of them have struck out on their own by introducing a number of amendments, something that is well within the rules, but a process that can slow down a bill's passage.

"I think it is the new people, keeners, if you will," Conservative Ontario Senator Bob Runciman said in an interview with CBC News. "Because right now it's pretty chaotic and there's a lack of organization."

The Senate has amended some 20 per cent of government bills that have received Royal Assent, compared to a standard amendment rate of just over 4 per cent before the start of this parliamentary session in November 2015, according to figures provided by the Independent Senators Group (ISG). Not all of the amendments were made by Independents.

An amended bill is then sent back to the House where amendments are either accepted or rejected, tacking on weeks to the parliamentary process.

"There's no negotiating positions because there's no caucus position," Liberal Newfoundland Senator George Baker, who was appointed by Jean Chrétien in 2002, said in an interview with CBC News. "So it removes the checks and balances that were in the Senate that protected the Senate from negating what the House of Commons passes, and that's what I think the political crisis is."

"How far can they go in amending legislation from duly-elected people? The Canadian people expect their elected representatives to represent them, to pass legislation. That's what they're elected for," he said. "The Senate has got to accept that elected representatives are ultimate boss; those Independent members need to realize that their actual role is limited."

Senator Peter Harder, the Trudeau government's representative in the Senate, has not used debate-limiting parliamentary tools like time allocation or closure. (Adrian Wyld/Canadian Press)

Peter Harder, the government's representative in the Senate, has also been loath to use parliamentary tools to shut down debate and force a vote on government legislation, namely the imposition of time allocation or closure. (He never has.) As a result, government legislation has moved through the Senate at a far slower than normal pace.

Take, for example, Bill C-4, which would reverse a number of Harper-era changes to labour legislation. The bill was first introduced in January 2016. It only passed through the Senate on Wednesday, some 18 months later.

Conservative senators, still the largest caucus in the Red Chamber, have also sought to further debate on legislation by using some procedural tricks that punt votes to a later date. Bill C-16, the transgender rights bill, spent months at the second reading phase of the legislative process prompting accusations of stall tactics. The government's immigration legislation, Bill C-6, was also debated for 81 sitting days.

3. The Trump factor

The above factors were compounded in the last six months by the election of U.S. President Donald Trump, who threw a wrench in the Liberal government's plans.

Trudeau has dispatched many cabinet ministers south since Trump's election, and has made one official trip to Washington himself. (Sean Kilpatrick/Canadian Press)

In order to avoid major diplomatic disruptions, the government has dispatched many cabinet ministers and senior officials to the U.S. in an effort to shore up relations, make inroads with friendly members of Congress, and sell Canada to an electorate that just supported an 'American First' president.

"There's always something going on. And you always have to manage the relationship," Gary Doer, Canada's former ambassador to the U.S., said in an interview.

"You're dealing with 50 governors and you're dealing with a cabinet and a president, so yeah, it takes a lot of time [and] you've got to be focused on that morning, noon and night."