Washington, September 28: Democratic presidential challenger Joe Biden slightly boosted his edge in both national and battleground polls within the past week, while President Donald Trump is already preparing to legally contest the outcome based on concerns over mail-in ballot fraud.

Because of the COVID-19 crisis, a record number of voters will be submitting ballots by mail in this year's presidential election. Experts predict that some 80 million people are expected to vote by mail, The New York Times reported.

Compare this to 2016 when roughly 33 million Americans voted by mail (including 24.8 million absentee ballots), according to the U.S. Election Assistance Commission.

Last month, a Democracy Fund/UCLA (University of California, Los Angeles) poll found that Biden voters are twice as likely to vote by mail compared to Trump supporters. Hence why the president has repeatedly claimed that casting ballots by mail will lead to widespread voter fraud. US Elections 2020: Presidential Debate Between Donald Trump and Joe Biden Begins on Tuesday; Know All About The Debate, Schedule And Where to Watch Live Streaming.

In fact, Trump last week predicted that the election will be decided before the Supreme Court, which is why he is fast-tracking the confirmation of his high-court nominee to replace the recently-deceased liberal-leaning justice Ruth Bader Ginsburg.

On Sunday, Politico reported, citing Republican Party officials, that the Trump campaign has hired dozens of lawyers and recruited thousands of volunteer attorneys and poll watchers ahead of the November election.

The Republicans are likely to dispute election results by questioning the authenticity of mail-in ballots and closely monitoring if the ballots arrive on time and are properly counted.

As of Sunday evening, according to the average of the most recent 10 surveys published in the past week on poll aggregator Realclearpolitics.com (http://realclearpolitics.com/) (RCP), the former vice president leads by 7 percent nationally, a half-point higher than last week. Biden's lead nationally in the RCP average has hovered around seven points over the past 30 days - reaching no higher than 8 percent, yet falling no lower than 6 percent.

Moreover, Biden is in a much better position than Hillary Clinton was four years ago. Consider that 37 days before election day in 2016, the RCP had Clinton ahead nationally by only 2.3 percent.

Given the structure of the Electoral College, however, national surveys are less significant than polling in key battleground states. That said, the state-level polling reveals that if the election were held today, Biden would win by a landslide.

Biden still leads in eight of the top 10 largest battleground states, the sum of which accounts for nearly 35% of the total electoral votes (538) apportioned across 50 states. A candidate needs to secure at least 270 electoral votes to win the presidential race.

The RCP shows Biden's lead within the past seven days edged up by less than one percent in 5 states: Pennsylvania (+4.6 per cent), Ohio (+3.3), Michigan (+5.2), North Carolina (+1.0), and Wisconsin (+7.0). His largest lead is in the state of Minnesota which saw a slight dip from 10% to 9.4 per cent, according to the RCP average.

Trump narrowed Biden's lead in Florida from 1.6 per cent to 1.3 per cent and by 1.6 percent to 3.4 per cent in Arizona. Trump's lead in Texas grew by just over one point to 3.6 per cent and remained steady in Georgia at 1.3 percent. RCP's "no toss-up" map shows Biden winning 27 states accounting for 353 electoral votes versus 23 states and 185 votes for Trump.

However, there still is a "path to victory" for Trump considering Biden's lead in five battleground states is under five percent. It is conceivable that Trump could defy the polls in these five states, which represent 93 electoral votes, to swing the Electoral College in his favour.

In addition, the performance of the candidates in Tuesday's presidential debate, the first of the campaign, could have a measurable impact on polling numbers. US Elections 2020: Donald Trump and Joe Biden to Face Off in First Presidential Debate Tomorrow.

SENATE UP FOR GRABS

The Republicans are hoping to maintain control of the 100-member Senate where they have a 53-seat majority. If the election were held today, the Democrats would end up with a 51 to 49 majority, although eight of the 35 races up for grabs this year are in the "toss-up" category.

Of the eight toss-up races, the most surprising is in South Carolina, where Republican incumbent Senator Lindsey Graham's lead has shrunk to one percent. In Arizona, Democratic candidate Mark Kelly leads Republican incumbent Martha McNally by 5.2%, a point less than last week.

Republican Thom Tillis in North Carolina is also in jeopardy of losing his seat with challenger Cal Cunningham extending his lead by over 2 points to 6% in the past week. Two other Republican incumbents down in the polls include Iowa's Joni Ernst (-2.6) and Maine's Susan Collins (-6.5).

Two other Republican senators have maintained tight leads including Georgia's David Perdue (+3.6 per cent) and Montana's Steve Daines (1.6 per cent). Finally, Michigan Democratic incumbent Gary Peters widened his lead by one percent to 4.6 per cent.

Meanwhile, the Democrats appear to be in a good position to maintain control of the 435-member House of Representatives, where they have a 36-seat edge. All 435 seats will be on the November 3 ballot.

The Democrats have a solid lead in 214 races to 190 for the Republicans with 31 in the toss-up category, according to RCP, the same tally as last week. The Democrats need to win at least 218 seats to maintain majority control.